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Strawberry Mousse Cake

This strawberry mousse cake recipe is made with soft white cake layers, the fluffiest strawberry mousse cake filling, and strawberry buttercream frosting.

It tastes just like summer and is absolutely delicious!

image of a slice of strawberry mousse cake that's been cut into to show how delicious it is

How to Make This Strawberry Mousse Cake

To make sure your strawberry mousse layer cake turns out as amazing as possible, let’s walk through each step together!

I’ve also included a video tutorial of the process below.

Step 1: Make the Strawberry White Chocolate Mousse

Make the strawberry mousse first so it has time to chill. It can also be made 1-2 days ahead of time.

Melt the white chocolate by placing it in a medium-sized, heat-proof bowl with heavy cream.

Heat for 45-60 seconds, until the chocolate is completely melted and smooth, then set aside. This can also be done in a double boiler.

image of white chocolate and heavy cream being melted down together to make a thin ganache as a base for a white chocolate mousse

Add the heavy cream, freeze dried strawberry powder, powdered sugar, vanilla extract, and a pinch of fine salt into a large bowl or the bowl of a stand mixer fit with a whisk attachment.

Mix on medium-high speed until the whipped cream starts to gather in the whisk attachment and you can see texture around the edges of the bowl (see photo below).

At this stage, the whipped cream should be thick and able to keep its shape.

This usually takes about one to two minutes in my stand mixer.

image of strawberry whipped cream that's been whipped until it reached stiff peaks

Gently fold the strawberry whipped cream into the white chocolate mixture in two additions.

Use a rubber spatula to swoop around the sides of the bowl and pull through the center like I show in the video of this recipe.

image of strawberry mousse being mixed together in a glass bowl

Be careful not to over-mix the mousse, or it will become deflated and lose its structure.

Cover the mousse with plastic wrap and chill in the refrigerator for at least 2 hours.

Make sure you keep the mousse chilled until right before you fill the cake because it can also lose its shape if it gets warm.

Step 2: Bake and Level the Vanilla Cake Layers

Next, make the vanilla cake batter. Divide the batter evenly between the prepared cake pans.

Bake for 45-50 minutes or until a toothpick comes out with a few moist crumbs.

image of an 8 inch cake pan being filled with fluffy white cake batter to make a strawberry mousse cake

Remove the cake layers from the oven and let them cool in the pans for about 10 minutes.

Gently run an offset spatula around the rim of the cake pans to loosen them, then flip them into wire racks to finish cooling.

Once the cake layers have cooled to room temperature, use a serrated knife to level the top of each cake layer.

It makes the cake so much easier to stack and assemble!!

image of a fluffy white cake later being leveled with a serrated knife

If you’re making these in advance, you can wrap and freeze them at this point.

Step 3: Make the Strawberry Buttercream

While the cake layers bake and cool, make the strawberry buttercream.

This frosting can also be made in advance if needed and kept in the fridge for up to a month!

If your frosting seems too thick after mixing your ingredients, add in additional cream (1 tablespoon at a time).

Or if the frosting is too thin, add in more powdered sugar (quarter of a cup at a time).

image of strawberry American buttercream being mixed together in a stand mixer

If you’re unsure how thick your frosting should be, you can learn what consistency you’re looking for in my frosting consistency post.

Step 4: Stack and Fill the Cake Layers

Stack and frost the cake layers on a greaseproof cake board using a dab of strawberry buttercream to help stick the first cake layer to the board.

Pipe a ring of strawberry buttercream around the perimeter of each cake layer.

Spread 1/4 cup of strawberry jam inside the frosting ring, then top it with an even layer of strawberry mousse. Use about 1/2 of the mousse between each layer.

image of a cake being filled with strawberry mousse cake filling

Repeat with the remaining cake layers. Once all the cake layers are stacked, spread a thin coat of frosting around the cake to fully cover the cake layers. This is called a crumb coat!

Smooth the frosting around the cake with a bench scraper, then freeze the cake for about 10 minutes in the freezer.

This will help the buttercream between the cake layers firm up and make the cake way easier to frost.

image of a strawberry cake being crumb coated

If you find your cake layers are sliding around as you try to frost the cake, you can insert a chopstick or wooden dowel into the center to keep the cake from sliding.

Step 5: Decorate This Strawberry Mousse Cake

Add a second, thicker layer of strawberry frosting to the cake and smooth using a bench scraper.

Then decorate as desired! I chose to add some buttercream swirls and small strawberries in a semi-circle on top of the cake.

I also add a few fresh flowers, but they were not edible and solely for decoration! They were removed before serving this cake.

image of a strawberry cake that's been decorated with small strawberries and frosting dollops from an overhead vantage overhead

Substitutions & Swaps: Fluffy White Cake Layers

While I love this strawberry mousse cake recipe just the way it is, I know some of you might not have all these ingredients on hand.

Below are some swaps and substitutions that can be made in this recipe:

  • Cake Flour – This recipe turns out best with cake flour. If you can’t find cake flour, you can make your own makeshift cake flour using this method. You can also swap in a good gluten free flour blend (like this) if needed. Just be sure to stir the batter longer than normal to help give the cake proper structure, and let the batter sit for about 20 minutes before baking it if you opt to make a gluten free version.
  • Granulated Sugar – I do not recommend reducing the amount of sugar or changing the type of sugar, as it will change the texture of the cake layers.
  • Sour Cream – You can also use full fat yogurt, buttermilk, whole milk, or an alternative yogurt or milk (almond, soy, oat).
  • Vegetable Oil – Use any flavorless oil can in this recipe. Canola, vegetable, or even sunflower oil would all work great. I don’t recommend olive oil though, as it has a strong flavor and will change the taste of the cake.
  • Egg whites – This recipe uses large egg whites. I like to use the type that come in a carton so that I don’t have to separate my eggs, but you can also use fresh egg whites. If you have an egg allergy you can try using a vegan egg replacer. You can also use 5 large, whole eggs but they will change the texture of the cake layers a bit.
image of a fluffy white cake that's been filled with strawberry mousse, strawberry jam, and frosted with strawberry buttercream

Substitutions & Swaps: Strawberry Buttercream & Mousse

Some swaps and substitutions that can be made in this frosting recipe include:

  • Unsalted Butter – If you only have salted butter on hand, you can use it in place of the unsalted butter. Just be sure to omit the salt that this frosting recipe calls for. You can also use vegan butter in its place!
  • Heavy Cream – Coconut cream can be used in place of the heavy cream as a dairy-free alternative.
  • White Chocolate – You can use white chocolate chips or good-quality white chocolate bars to make the strawberry mousse.
  • Freeze Dried Strawberry Powder – This is an absolute must in this recipe to make both the strawberry mousse and the strawberry buttercream! I order mine online, but you can also buy freeze dried strawberries and grind them in a spice grinder or food processor.
  • Strawberry Jam – I love using my mom’s strawberry freezer jam in this recipe, but any strawberry jam or jelly should work great!
image of freeze dried strawberry powder

Tips for Making the Best Strawberry Mousse Cake

  • When making the strawberry mousse, chill your mixing bowl and whisk attachment in the freezer. It makes it easier and quicker to whip up the whipped cream for the mousse.
  • Properly measure your flour (spoon into the cup measure, then level). Or better yet, use a kitchen scale to measure your dry ingredients.
  • Mix the cake batter just until the ingredients are incorporated once you add in the flour. This will ensure your cake layers are tender and fluffy.
  • Use a scale to weigh your cake pans as you fill them. It will make your cake layers bake to the same height and bake more evenly.
  • Bang your cake pans on the counter before putting them in the oven. This brings any big air bubbles that are trapped in the batter to the surface.
  • Level your room temperature or thawed cake layers with a serrated knife to make them easier to stack.
  • Chill your cake layers in the freezer for about 20 minutes before assembling the cake. It makes it so much easier to stack and frost them!
image of a slice of strawberry mousse cake that's been placed on a plate

Making This Strawberry Mousse Cake in Advance and Storage Tips

Make your cake layers in advance and freeze them. It breaks the process up and makes it more approachable.

The strawberry mousse can also be made in advance! Make it up to 2 days in advance and store in the fridge.

Make the strawberry frosting ahead of time or save any leftover frosting. Store in an airtight container in the fridge for up to a month.

This frosting can also be stored in the freezer for up to 3 months! Just be sure to give it a good stir once it thaws to make it nice and smooth again. This cake can last in the fridge for up to 2 days.

image of a bite of strawberry mousse cake on a fork

Let Me Know What You Think

If you try this strawberry mousse cake recipe, I’d love to hear what you think! Please leave a comment and rating below.

And don’t forget to tag me @chelsweets and #chelsweets so that I can see your delicious creations on social media!

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Yield: 24

Strawberry Mousse Cake

image of a slice of strawberry mousse cake that's been cut into to show how delicious it is

This strawberry mousse layer cake recipe is made with fluffy white cake layers, the fluffiest strawberry mousse filling, and strawberry buttercream frosting.

Prep Time 15 minutes
Cook Time 45 minutes
Additional Time 2 hours
Total Time 3 hours

Ingredients

Strawberry Mousse

  • 1 cup good quality white chocolate chips (180g)
  • 1 1/3 cups heavy cream or heavy whipping cream, cold - divided (320g)
  • 1/2 cup freeze dried strawberry powder (56g)
  • 1/4 cup powdered sugar (30g)
  • 1 tsp vanilla extract (4g)
  • pinch of fine salt (less than 1/8 tsp)
  • red gel food coloring - optional

White Cake Recipe

  • 1 cup or 2 stick unsalted butter, room temperature (226g)
  • 3 cups granulated sugar (600g)
  • 1 cup pasteurized egg whites from a carton or about 7 egg whites, room temperature (235g)
  • 3 cups cake flour (360g)
  • 2 1/2 tsp baking powder (10g)
  • 1 tsp salt (6g)
  • 1 1/2 cups full-fat sour cream, room temperature (380g)
  • 1/4 cup vegetable oil (56 ml)
  • 1 tsp vanilla extract (4ml)

Strawberry Buttercream Frosting

  • 1 1/2 cups unsalted butter, room temperature (339g)
  • 1/2 cup freeze dried strawberry powder (56g)
  • 1 tsp vanilla extract (4ml)
  • 1/2 tsp salt (3g)
  • 5 cups powdered sugar (625g)
  • 1/4 cup strawberry jam (80g)
  • 1 Tbsp lemon juice (12g)

Additional Filling

  • 1/2 cup strawberry jam (160g)

Tools and Equipment Needed

Instructions

Strawberry Mousse Cake Filling

  1. Make the strawberry mousse first so it has time to chill. Or better yet, make this mousse in advance! It can be made 1-2 days ahead of time.
  2. Add 1 cup white chocolate chips and 1/3 cup heavy cream in a medium-sized, heat-proof bowl. Heat for 45-60 second in the microwave, then let the mixture sit for a minute. Stir until combined with a rubber spatula. The white chocolate should be completely melted, and the mixture should be smooth. If you don't have a microwave, you can also use a double boiler. Set aside.
  3. Add 1 cup of heavy cream, 1/2 cup freeze dried strawberry powder, 1/4 cup powdered sugar, 1 tsp vanilla extract, and a pinch of fine salt into a large bowl or the bowl of a stand mixer fit with a whisk attachment. If desired, add a small drop of red gel food coloring to give this mousse a more vibrant color.
  4. Mix on a medium-high speed until the whipped cream starts to gather in the whisk attachment and you can see texture around the edge of the bowl. The whipped cream should be thick and able to keep its shape. This usually takes about a minute or two in my stand mixer.
  5. Gently fold half of the strawberry whipped cream into the white chocolate mixture using a rubber spatula. Use the spatula to swoop around the sides of the bowl and pull through the center like I show in the video of this recipe. Fold in the remaining strawberry whipped cream. Be careful not to over-mix the mousse, or it will become deflated and lose its structure.
  6. Cover the mousse with plastic wrap and chill in the refrigerator for at least 2 hours. Make sure you keep the mousse chilled until right before you fill the cake because it can also lose its shape if it gets warm.

White Cake Layers

  1. Preheat oven to 325°F / 162°C. Line and grease three, 8-inch cake pans with parchment rounds.
  2. Add 1 cup of unsalted butter and 3 cups of granulated sugar into the bowl of a stand mixer. Mix together on a high speed with a whisk attachment for 3 minutes. Scrape down the sides of the bowl as needed with a rubber spatula. The mixture should become lighter in color as air is whipped into it.
  3. Add in 1 cup of room temperature egg whites and mix at a medium speed until they're incorporated.
  4. Whisk 3 cups of cake flour, 2 1/2 tsp baking powder, and 1 tsp salt together in a separate bowl.
  5. Add half of the dry ingredients into the butter/egg mixture and mix on a low speed until incorporated.
  6. Add in 1 1/2 cups sour cream, 1/4 cup oil, and 1 tsp vanilla extract and mix at a low speed until combined. Scrape the sides and bottom of the bowl as needed.
  7. Mix in the remaining dry ingredients on a low speed.
  8. Divide the batter evenly between the prepared cake pans. I like to use a digital kitchen scale to weigh my pans to make sure my layers bake up to be the same height.
  9. Bake for 45-50 minutes, or until a toothpick comes out with a few moist crumbs. Rotate the pans halfway through to help them bake evenly. I know this seems like a long time, but it takes a bit longer than normal because we're baking these at 325°F / 162°C.
  10. Let the pans cool for 10 minutes, then run an offset spatula around the perimeter of the pan to separate the cake from the pan.
  11. Place the cake layers into the freezer for 45 minutes to accelerate the cooling process. Once the layers are fully cooled, carefully flip the pans and remove the layers from the pans.
  12. Use a serrated knife to level the top of each cake layer.

Strawberry Buttercream Frosting

  1. While the cake layers bake and cool, make the strawberry buttercream frosting.
  2. Beat 1 1/2 cups butter on a low speed for 30 seconds with a paddle or whisk attachment until smooth.
  3. Add in 1/2 cup freeze dried strawberry powder, 1 tsp vanilla extract, and 1/2 tsp salt and beat on a low speed.
  4. Gradually mix in 5 cups of powdered sugar on a low speed. Add in 1/4 cup of strawberry jam and 1 Tbsp of lemon juice halfway through to make the frosting easier to mix.
  5. Continue to mix until the ingredients are fully incorporated, and the desired consistency is reached. 
  6. If the frosting seems too thick, add in additional cream (1 teaspoon at a time). If the frosting is too thin, add in more powdered sugar (quarter of a cup at a time).
  7. Stir by hand with a rubber spatula to make the frosting extra smooth, then place the frosting in a large piping bag. Seal the top of the bag with a rubber band or clip and cut an opening that's about 3/4-inch wide at the base of the bag. Set aside.

Assembling This Strawberry Mousse Cake

  1. Stack and frost the cake layers on a greaseproof cake board using a dab of frosting to help stick the first cake layer to the board.
  2. Pipe a ring of strawberry buttercream around the perimeter of the cake layer. Spread 1/4 cup of strawberry jam inside the frosting ring, then top it with an even layer of strawberry mousse. Use about 1/2 of the mousse between each layer.
  3. Repeat with the next cake layer. Once all the cake layers are stacked, spread a thin coat of frosting around the cake to fully cover the cake layers. If your layers are sliding around, insert a chopstick or wooden dowel into the center of the cake to make it more stable.
  4. Smooth using a bench scraper, then chill the cake in the fridge (30 minutes) or freezer (10 minutes) until the frosting is firm to the touch.
  5. Add a second, thicker layer of strawberry buttercream to the cake and smooth using a bench scraper.
  6. Then decorate as desired! I chose to add some buttercream swirls and small strawberries in a semi-circle on top of the cake.

Notes

Tips for Making the Best Strawberry Mousse Cake

  • When making the strawberry mousse, chill your mixing bowl and whisk attachment in the freezer. It makes it easier and quicker to whip up the whipped cream for the mousse.
  • Properly measure your flour (spoon into the cup measure, then level). Or better yet, use a kitchen scale to measure your dry ingredients.
  • Mix your cake batter just until the ingredients are incorporated after adding in the flour. This ensures your cake layers are tender and fluffy.
  • Use a scale to weigh your cake pans as you fill them. This will make your cake layers bake to the same height and bake more evenly.
  • Bang your cake pans on the counter before putting them in the oven. This brings any air bubbles that are trapped in the batter to the surface.
  • Level your room temperature or thawed cake layers with a serrated knife to make them easier to stack.
  • Chill the leveled cake layers in the freezer for about 20 minutes before assembling the cake. It makes it so much easier to frost them!

Making This Strawberry Mousse Cake in Advance and Storage Tips

  • Make your cake layers in advance and freeze them. It breaks the process up and makes it more approachable.
  • Make your frosting ahead of time too or save any leftover frosting! It can be stored in an airtight container in the fridge for up to a month, or in the freezer for up to 3 months. Be sure to give it a good stir once it thaws to get the consistency nice and smooth again.
  • The strawberry mousse filling in this cake can be made up to two days in advance if stored in an airtight container in the fridge.
  • A frosted cake can last in the fridge for up to 2 days.

Nutrition Information

Yield

24

Serving Size

1

Amount Per Serving Calories 628Total Fat 33gSaturated Fat 18gTrans Fat 0gUnsaturated Fat 12gCholesterol 81mgSodium 271mgCarbohydrates 80gFiber 1gSugar 62gProtein 5g

Michele Elliott

Thursday 4th of August 2022

Hi Chelsey, the recipe looks delicious and I've chosen to make it for a "football" birthday party. This cake will be the football field and I'll be making a chocolate football cake to put on top. My question is will it matter if I don't use 3 round cake pans and instead use a square 9X13 pan? I will be splitting the cake and filling it that way. I'm wondering if the cake will bake differently if it's all in one pan as opposed to 3 pans. Thank you for your expert advice!

Chelsweets

Sunday 7th of August 2022

Hi Michele,

That sounds like such a fun cake! This cake should bake up great as a sheet cake. I'd recommend baking it at 350 F / 175 C for 35-45 minutes and use a couple flower nails or heating cores (like these: https://amzn.to/2T0BlgV) to help the cake bake evenly. Also rotate the pan halfway through to make sure it rises evenly. I hope that helps, happy baking!

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