Tuxedo Cake

This tuxedo cake is my from-scratch take on the Costco tuxedo cake. It’s made with dense, fudgy chocolate cake layered with fluffy dark + white chocolate mousse.

It’s ultra-decadent but totally doable at home, with a rich chocolate ganache topping and an optional chocolate simple syrup for extra moisture.

This Recipe At a Glance

• Flavor: Deep chocolate with creamy dark + white chocolate mousse
• Texture: Dense/fudgy layers + light mousse filling
• Skill level: Intermediate (I walk you through each step)
• Perfect for: Birthdays, holidays, and Costco cake fans
• Makes: One 2-layer cake (9×13 cut in half or 2×9-inch layers) + mousse + ganache
• Time note: Needs chill time (mousse sets best after 2+ hours)

What is a Tuxedo Cake?

If you look up what a tuxedo cake is online, you’ll find a few different answers. While most involve a decadent chocolate cake base and white and chocolate ganache, that’s where the similarities end.

Costco’s tuxedo cake has become a fan favorite, and I think it’s the best example of what a classic tuxedo cake should be.

Costco adds brownie bits. This version skips them, but you can add 1/2–3/4 cup brownie bits or crushed Oreos between the mousse layers.

How to Make This Chocolate Tuxedo Mousse Cake

To make sure your chocolate tuxedo 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 White and Dark Chocolate Mousse

Make the white and dark chocolate mousse first, so it has time to chill and firm up.

Place a large mixing bowl and hand mixer beaters or the bowl of a stand mixer and whisk attachment in the freezer. This makes it easier and quicker to whip up the whipped cream for the mousse.

Melt the chocolate chips by placing them in a medium-sized, heat-proof bowl. Heat in 20 to 30-second increments in the microwave, stirring after each interval until the chocolate is completely melted and smooth.

In a small bowl, whisk together the warm water and cocoa powder. Pour into the melted chocolate and whisk together until smooth. The mixture should be somewhat thick. Set aside.

Then add the white chocolate chips and heavy cream in a medium-sized, heat-proof bowl. Heat for 45-60 seconds 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. Set aside.

Add the heavy cream, powdered sugar, vanilla extract, and a pinch of fine salt in a large bowl or the bowl of a stand mixer fitted 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.

At this stage, the whipped cream should be thick and able to keep its shape. This usually takes about 2-3 minutes in my stand mixer.

Scoop half of the whipped cream into a separate bowl, and mix in the chocolate/cocoa/water mixture using a rubber spatula.

Use the spatula to swoop around the sides of the bowl and pull through the center until the ingredients are fully combined. Be careful not to over-mix the mousse, or it will become deflated and lose its structure.

Pour the melted white chocolate/heavy cream mixture into the remaining whipped cream using a rubber spatula.

At this point, the white chocolate mixture should have cooled down a bit and should still be fluid, but shouldn’t be hot to the touch.

Use the spatula to swoop around the sides of the bowl and pull through the center.

Cover both bowls of mousse with plastic wrap or scoop each mousse into its own piping bag and chill in the refrigerator for at least 2 hours.

Step 2: Make the Chocolate Ganache Frosting

While the mousse chills, make the chocolate ganache frosting.

Add the heavy cream to a medium-sized bowl and heat it until it just begins to bubble. This can be done in either the microwave or a double boiler.

Then pour in the dark chocolate and corn syrup and let the mixture sit for a minute.

After a minute, the chocolate should be softened. Stir the mixture until the cream and chocolate are combined and the mixture is smooth.

If any bits of chocolate aren’t fully melted, heat the mixture again for 15 seconds and stir until smooth.

Then mix in the unsalted butter and fine salt.

Cover with plastic wrap placed flush against the top of the ganache to prevent it from forming a skin, then set aside to cool to room temperature.

If you need to make this topping in advance, it can be covered and stored in the fridge for up to a month.

The ganache should thicken and be scoopable once it reaches room temperature. If you want to accelerate the cooling process, place the bowl in the fridge.

Step 3: Bake and Level the Chocolate Cake Layers

Next, make the chocolate cake batter following the recipe card at the bottom of this post.

Preheat the oven and line and grease a 9×13-inch cake pan or 2, 9-inch cake pans with parchment paper and non-stick spray.

If you have heating cores, place two heating cores in the 13×9 pan or one heating core in each 9-inch pan and generously spray them with non-stick spray. This helps the cake bake up more evenly and quickly.

Pour the batter into the prepared pan(s). Bake a 9×13-inch pan for 40-45 minutes (add 3-5 minutes if you aren’t using heating cores), or bake 2, 9-inch cake pans for 34-37 minutes (add 2-3 minutes if you aren’t using heating cores).

Let the pans cool for 10 minutes, then run a small offset spatula around the perimeter of the pan to separate the cake from the pan.

Then place the cake layer(s), pan and all, into the freezer for 30 minutes to accelerate the cooling process. Once the layer(s) are fully cooled, carefully flip the pans and remove the layers.

Use a serrated knife to level the top of the layers. If you made a 9×13-inch cake, cut it in half to make 2, 9×6.5-inch pieces.

Wrap and freeze the layers at this point if you’re making them in advance. If you do make these cake layers in advance and freeze them, let them thaw for about 20 minutes before making this cake.

The cake layers should still be slightly cold to the touch, which will make it easier to assemble the cake.

Step 4: Make the Chocolate Simple Syrup

The chocolate simple syrup in this recipe is optional but recommended.

The cake bakes up pretty moist on its own, but I like to add simple syrup so it stays moist for several days, especially since the sides are exposed to air.

It only takes a couple of minutes to make, and I think it’s worth it!

After bringing the water and granulated sugar to a boil, remove the pan from heat and stir in the unsweetened cocoa powder. Then, pour the mixture into a separate container to cool.

Step 5: Stack and Fill the Cake Layers

Now that all our components are ready for this tuxedo cake, it’s time to assemble it!

Spread a bit of chocolate ganache on a grease-proof cake board or flat plate to help keep the cake in place, then center the first cake layer on top of the ganache.

If you made the chocolate simple syrup, generously brush it over the cake layer using a silicone brush or a clean kitchen brush.

Cover the cake in an even layer of dark chocolate mousse, then top it with an even layer of white chocolate mousse.

Place the remaining cake layer on top of the mousse and soak the top of the layer with chocolate simple syrup.

Use a small offset spatula or piece of acetate sheet to clean up the sides of the cake and give the mousse a sharp edge that’s flush with the cake layers.

Chill the cake in the fridge for 15 minutes to help it keep its shape. Then spread the chocolate ganache in a thick layer on top of the cake with a small offset spatula.

Decorate the top of the cake with chocolate sprinkles and chocolate pearls, then enjoy!

I like to cut and serve this cake cold straight out of the fridge, but you can also let it sit at room temperature for up to an hour before serving if you want it to be less cold.

I don’t recommend leaving this cake out at room temperature for longer than that, or else the mousse will deflate and lose its shape!

Substitutions & Swaps: Dark Chocolate Cake Layers

While I love this tuxedo cake 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:

• All-Purpose Flour – This recipe turns out best with AP flour, but you can use a gluten-free flour blend or cake flour if needed.
• 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.
• Dark Cocoa Powder – I like to use dark or Dutch-processed cocoa powder in this recipe. However, it would also taste great with regular cocoa powder, too!
• Unsalted Butter – If you only have salted butter on hand, you can use it in place of the unsalted butter in this recipe. Just be sure to omit the salt that this recipe calls for. You can also use vegan butter in its place (and also omit the salt)!
• Egg Whites – I like to use egg whites from a carton, but you can also use 4 large eggs in place of the egg whites in this recipe. Or, if you have an egg allergy, you can use a flaxseed egg or an egg replacer.
• Buttermilk – You can also use full-fat yogurt, sour cream, whole milk, or an alternative yogurt or milk (almond, soy, oat) if you’re dairy-free.
• Vegetable Oil – You can use any flavorless oil in this recipe. Canola or even sunflower oil would work great!

White and Dark Chocolate Mousse Substitutes

• White Chocolate – You can use good-quality white chocolate chips, baking chocolate, or white chocolate bars.
• Dark Chocolate – Any good-quality chocolate with 60% cocoa or more will work for the dark chocolate mousse.
• Heavy Whipping Cream – Use heavy cream or heavy whipping cream (milk fat % of at least 30%). To make dairy-free and vegan chocolate mousse cake filling, use coconut cream.
• Powdered Sugar – You need a fine sugar like powdered sugar to give the whipped cream a smooth consistency. I don’t recommend using granulated sugar or other types of sugar to make the mousse.

Making This Tuxedo Cake in Advance & Storage Tips

You can make these cake layers in advance and freeze them. It breaks the process up and makes it more approachable.

The white and dark chocolate mousse can also be made in advance! It can be made up to 2 days ahead of time and stored in the fridge.

You can also make the chocolate ganache frosting ahead of time or save any leftover frosting! Store it in an airtight container in the fridge for up to a month.

This cake can be stored in the fridge for up to 3 days or in the freezer for a month. I recommend covering the cake with plastic wrap or placing it in an airtight container to keep it moist.

Troubleshooting

Why is my white chocolate mousse too soft?

White chocolate mousse is naturally a bit softer than dark chocolate mousse, especially once it starts to warm up.

• Chill longer: Let the mousse (and the assembled cake) chill at least 2 hours so it can fully set.
• Assemble cold: Keep the cake layers and mousse cold while stacking. If your kitchen is warm, chill the cake between steps.
• Don’t overmix: Fold just until combined. Over-folding can deflate the whipped cream and make the mousse looser.
• Optional (for extra stability): If you need a firmer mousse for a hot day or travel, you can add a small amount of gelatin. Bloom 1 tsp powdered gelatin in 1 Tbsp water for 5 minutes. Microwave 5–10 seconds until fully liquid. Stir 1–2 Tbsp of the mousse base into the melted gelatin (this tempers it), then pour that mixture back into the mousse base while stirring. Then, fold in the whipped cream as usual.

Why is my cake sliding or the mousse squishing out?

This usually happens when the mousse is too soft at assembly time.

• Your chocolate base may have been too warm: If the melted chocolate/cream mixture is warm when you fold it into whipped cream, it can soften and deflate the mousse.
• Chill before stacking: If the mousse feels loose, refrigerate it for 20-30 minutes before assembling.
• Chill mid-assembly: After you stack and smooth the sides, chill the cake 15-20 minutes before adding ganache.
• Use a gentle touch: Pressing down on the top layer can push mousse out the sides. Set it on gently and chill in the fridge to help the cake fully firm up.

Why did my white chocolate seize or turn grainy?

White chocolate is finicky and can seize or separate if it overheats.

• Use low, gentle heat: Microwave in short bursts (10-20 seconds), stirring well between each burst.
• Stop before it looks fully melted: Let residual heat finish the job as you stir.
• Avoid overheating in certain bowls: Some bowls retain heat and can keep “cooking” the chocolate after the microwave stops.
• If it’s already grainy: Keep stirring first. If it stays separated/grainy, sadly, it’s best to remake it. Grainy white chocolate won’t fold smoothly into mousse.

Why is my ganache hard to cut or making the mousse ooze out?

A thick ganache layer can set firm in the fridge and squish the mousse when you slice.

• Keep the ganache layer thin: Pour just enough to cover the top. Thicker = firmer once chilled.
• Use a hot, dry knife: Run the knife under hot water, dry it off, then slice. Wipe and rewarm between cuts.
• Let it sit briefly before slicing: If the cake is rock-hard cold, let it sit 10–15 minutes so the ganache softens slightly (but don’t leave it out too long or the mousse will soften too much).

How am I supposed to cut the cake layers?

If you bake the cake in a 9×13-inch pan and cut it in half to stack, you’ll end up with two pieces that are about 9×6.5 inches each. Try to cut as evenly as possible so the layers stack neatly.

Frequently Asked Questions

Can I make this in round cake pans instead of a 9×13?

Yes. You can bake this in round pans instead of a 9×13. Round layers will usually need a bit longer in the oven. For 8-inch rounds, bake 3 layers at 350°F for 33–35 minutes.

Bake until the center is set, and a toothpick comes out with a few moist crumbs.

How far ahead can I make tuxedo cake?

This is a great make-ahead cake. You can bake the cake layers 1-2 days ahead (wrap tightly and refrigerate) or freeze them for longer storage. The mousse layers need chill time to set, so I recommend assembling the cake at least a few hours before serving (or the day before).

Can I freeze tuxedo cake (with mousse)?

Yes. Freeze the fully assembled cake until firm, then wrap it well. Thaw overnight in the fridge before serving. For the cleanest slices, cut it cold and wipe your knife between cuts.

Do I have to use Dutch-processed cocoa?

No. Dutch-processed cocoa gives a deeper, darker chocolate flavor, but regular unsweetened cocoa will still work. The cake may be slightly lighter in color and a bit less intense in chocolate flavor.

How do I get clean slices?

Chill the cake well, then use a hot, dry knife (run it under hot water, dry it off, slice, wipe, repeat). If the ganache is very firm, let the cake sit 10-15 minutes before slicing so it softens slightly.

Tips for Making the Best Tuxedo Cake

• When making the dark chocolate and white chocolate 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.
• Ingredients at room temperature mix together better! Set out any cold ingredients that need to be at room temperature ahead of time.
• Properly measure the flour (spoon it into the cup measure, then level it). Or better yet, use a kitchen scale to measure your dry ingredients.
• Level your room temperature or thawed cake layer(s) with a serrated knife to make them easier to stack.
• Chill your cake layer(s) in the freezer for about 20 minutes before assembling the cake. It makes it so much easier to stack and frost them!

Let Me Know What You Think

If you try this tuxedo cake recipe, I’d love to hear what you think! Please leave a rating below and a comment to let me know your thoughts.

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