Raspberry Cake Filling

A couple weeks ago I made a white chocolate raspberry cake, and the real star of the show was its raspberry cake filling!

It was deliciously sweet and tart, and the perfect consistency to fill a cake.

The cake recipe was a pretty detailed, so I wanted to make a post sharing just the raspberry filling. I also think this will encourage people to get creative and add this filling to their favorite cake and cupcake recipes.

image of white cake with delicious tart raspberry cake filling

This filling would be incredible with my chocolate layer cake recipe, or even my matcha cake recipe. The sky’s the limit!!

Giving This Raspberry Cake Filling Its Silky-Smooth Texture

I love the texture of seeds in a fresh raspberry and in raspberry jam, but I have strong feelings when it comes to the texture of raspberry filling. It really needs to be seedless.

Raspberry filling is usually made with fresh or frozen raspberries that are cooked down to help concentrate the mixture.

image of raspberry cake filling being cooked down on a stove top in a sauce pot

This thickens the mixture and enhances the flavor of the filling.

When doing this, the seeds in the mixture also become more concentrated.

If you don’t strain the mixture, the texture of the seeds can be overwhelming. I think the filling is so much better without the seeds!!

The photo below shows the filling after it was strained, but before it was thickened with the cornstarch slurry.

image of stained raspberry cake filling, before being thickened with cornstarch

My Advice: Use A Strainer

I hate straining things, but this is one situation where I’m willing to whip out my mesh strainer and put in the work.

This helps us get the filling to have that gorgeous consistency shown in the photo above.

image of pouring raspberry compote through a strainer to make it seedless for a cake filling

The mixture is pretty thick once it’s been cooked down, so you really need to push firmly with a rubber spatula to get it through the sieve.

It takes a few minutes to do, and is a bit of an arm workout.

But it is 100% worth it!! You should be left with about ½ cup concentrated raspberry seeds, which can be composted.

image of leftover raspberry seeds after straining raspberry compote

Frozen vs. Fresh Raspberries

I test out this recipe with both fresh raspberries and frozen raspberries. Both types work great, so you can make this recipe with either!

If raspberries are in season, using fresh raspberries is a great idea! Frozen raspberries work great in the offseason, or if you can’t get your hands on fresh raspberries.

Frozen raspberries are also quite a bit cheaper than fresh raspberries. For convenience I like to use frozen raspberries, because I don’t have to worry about them spoiling if I don’t use them immediately.

image of the ingredients used in this raspberry cake filling including frozen raspberries, sugar, and lemon juice

I also think that frozen raspberries are picked at peak ripeness, while some fresh raspberries are picked before they’re fully ripe to make transportation easier.

Getting the Consistency Just Right For a Cake

While cooking down the raspberries does thicken the mixture, it doesn’t make it quite thick enough to add to cake.

If you’ve never tried to add a bunch of jam between the layers of a tall cake, you know that you need a thick filling or else your cake layers slide all over the place!

I like to call it the slip and slide, and it makes cake decorating a nightmare.

image of fluffy and soft white cake layers filled with white chocolate buttercream and a raspberry filling

You also need a cake filling to be thick to ensure it won’t ooze out the sides of your cake once it’s stacked and frosted.

Even with the help of a piped ring of frosting (i.e. a frosting dam), the filling can still ooze out as the cake settles.

Trust me, I’ve had my share of oozing fruit-filled cakes, and nothing is worse!!

Thickening This Raspberry Cake Filling with Cornstarch

This recipe is designed to make a really thick filling once it’s fully cooled.

It ends up being just about as thick as jelly. The secret to making this raspberry cake filling so thick is cornstarch!

This recipe adds a slurry (a mixture of cornstarch and water) to the partially cooked down raspberry mixture.

image of raspberry cake filling in a bowl

Using a slurry rather than adding cornstarch directly into the filling makes it so much easier to incorporate the cornstarch into the filling.

I hate making extra dishes, but you simply can’t add the cornstarch straight into the raspberry mixture.

I’ve tried it, and you end up with tons of tiny clumps of cornstarch in your filling!!

My Secret Ingredient

Whenever I make anything with strawberries or raspberries, I love to incorporate a bit of fresh lemon juice and zest. This recipe uses both!

I think it really enhances the flavor of the fruit, and adds a bright pop of flavor.

Just be sure you a fresh lemon! Pre-squeezed lemon juice doesn’t have the same effect.

image of slice of white chocolate raspberry cake

Even if you plan to add this filling to something with chocolate in it, I still recommend adding the lemon.

The lemon really just acts an accent, and isn’t a dominant flavor in the filling.

Tips for Making the Best Raspberry Cake Filling:

  • Make the raspberry cake filling at least a day in advance to allow it to properly thicken and develop its flavor
  • Be sure to use fresh lemon juice and zest, to enhance the tartness of the raspberries
  • Strain the raspberry mixture to remove the seeds, to give it a silky-smooth texture
  • Save leftover filling to fill cupcakes, add to thumbprint cookies, or even to top ice cream!

Making This Cake in Advance and Storage Tips:

  • This raspberry cake filling can be made up to two weeks in advance if stored in an airtight container in the fridge
  • This raspberry cake filling can be stored in the freezer up to a month if stored in an airtight container
  • Give the filling a stir with a rubber spatula before adding it to your cake to make it easier to spread
image of raspberry white chocolate cake decorated with fresh raspberries, flowers, and a white chocolate drip with slice in front

Let Me Know What You Think

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

Yield: 1.5

Raspberry Cake Filling

image of slice of white chocolate raspberry cake

This raspberry cake filling is the perfect consistency, and is packed with that delicious tart raspberry flavor! It's sure to elevate any dessert!! It's great inside of cakes, cupcakes, and even cookies.

Prep Time 20 minutes
Cook Time 10 minutes
Total Time 30 minutes

Ingredients

Raspberry Cake Filling

  • 4 cups of fresh or frozen raspberries (500 grams)
  • 3/4 cup granulated sugar (150 grams)
  • 1 Tbsp lemon juice (12 grams)
  • 2 tsp fresh lemon zest (5 grams)
  • 1/2 cup water, divided (118 grams) - half added to raspberry mixture, half used to make the cornstarch slurry
  • 1/4 cup cornstarch (31 grams)

Equipment Needed

Instructions

Raspberry Cake Filling

  1. If possible, make the raspberry filling in advance! The extra time will allow the filling to thicken and develop its flavor.
  2. Place the frozen or fresh raspberries, granulated sugar, lemon juice and lemon zest, and 1/4 cup of water in a saucepan and heat over medium high heat.
  3. Stir the mixture until it begins to boil.
  4. Lower the heat to medium-low, and allow the filling to simmer for 10-15 minutes.
  5. Turn off heat and remove the pot from the stove. Pour the filling into a metal strainer suspended over a medium sized bowl, and push through using a rubber stapula. Use a decent amount of pressure to really get all the liquid through the sieve. You should be left with about 1/2 cup of seedy pulp.
  6. In a separate small bowl, make a slurry by combine the remaining 1/4 cup of water with the cornstarch. Stir until the cornstarch has fully dissolved into the water.
  7. Add this cornstarch mixture into the strained raspberry filling, and stir until it is incorporated.
  8. Rinse out your pot and pour the filling back into it (you don't want any residual seeds getting into the filling).
  9. Heat at a medium high heat, and be sure to stir constantly during this stage to prevent the filling from burning.
  10. Cook until the mixture begins to boil, then reduce the heat to medium low.
  11. Continue to stir, and cook for a few additional minutes.
  12. Turn off heat and pour the raspberry filling into a separate bowl to cool. Cover with plastic wrap and place in the fridge for at least 1 hour, or preferably overnight.

Notes

This recipe makes about 1.5 cups of raspberry cake filling, which is enough to fill an 8-inch layer cake.

Making This Cake Filling in Advance and Storage Tips:

  • This raspberry cake filling can be made up to two weeks in advance if stored in an airtight container in the fridge
  • A frosted cake filled with this raspberry cake filling can last in the fridge for up to a week, or in the freezer for up to a month. The buttercream locks in all the moisture, keeping the cake fresh and delicious!

Nutrition Information

Yield

1.5

Serving Size

1

Amount Per Serving Calories 1667Total Fat 7gSaturated Fat 0gTrans Fat 0gUnsaturated Fat 1gCholesterol 3mgSodium 609mgCarbohydrates 401gFiber 55gSugar 191gProtein 12g

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25 thoughts on “Raspberry Cake Filling

  1. I made your white chocolate raspberry cake this weekend and it was amazing! Only problem is that this raspberry filling turned into what I can only describe as jello. I followed the recipe exactly, so I’m wondering if maybe I should go lighter on the cornstarch?

    1. Hi Marissa,

      It does set pretty stiff, but usually if you give it a good stir it’s spreadable again! You can add less cornstarch if you want, but I find if it’s thinner than that jello-esque consistency it can ooze out the sides of the cake as the cake settles. Hope that helps, happy baking!

  2. Hi Chelsea. I was stupid and used a different raspberry filling recipe and now it’s too runny. How can I thicken it up? I’m definitely using yours next time! Thanks!

    1. No worries Mel! You can make a slurry of cornstarch and water, and add it the rasp filling over a medium heat! the combination of cornstarch plus the heat should thicken yours up. Hope that helps, happy baking!

    1. Hi Lynda,

      As long as you pipe a frosting dam around the filling, it should work great in a tiered fondant cake. Hope that helps, happy baking!!

  3. This filling is great! I was looking for a good thick consistency and this is it. I also tried it with Strawberries and it was just as yummy. Thank you!!!

  4. I thought it sounded like too much cornstarch but my rule is that the first time I make something I follow the recipe exactly. In this instance I should have gone with my instincts because what I ended up with was an unspreadable red jello that could not be salvaged.

  5. This was so yummy!!!! My daughter wanted a chocolate cake with raspberry filling for her birthday. Your recipe was perfect!

  6. Great flavour and consistency. I made a white chocolate raspberry three layered cake and used you filling recipe which turned out perfect.

    I used frozen raspberries and followed the directions exactly and had a little extra filling left over. Cake was a big hit at work. Thanks for a great recipe.

  7. Hello! I recently made this recipe and it was great. I made it again (a double batch) and put it in the fridge a week ago, and today I saw that it had separated sort of?? There was a hunk of raspberry jello surrounded by raspberry liquid. I blended it back together with a hand blender but it’s a softer consistency than when I put it in the fridge initially. I also noticed it has a more cornstarchy mouthfeel. I’m wondering if I did something wrong, or maybe a week in the fridge is too long?? I need it for a wedding cake and I’d hate to have to remake it last minute, is there a way to thicken it back up just a bit?

    1. Hi Janette,

      I usually use one batch of batter to make 2 9×13″ sheet cakes that are about 1 inch tall! You could probably use one batch to make a half sheet cake that’s slightly taller. Hope that helps, happy baking!

  8. Hoping in this hot weather has to have success with a chocolate cake with raspberry compote in between the layers. You mentioned that it will make an 8 inch layer cake I’m looking for a three tier possibly 40 or 6 inch cake. Will this work or do I need to double the recipe

  9. I made the raspberry filling earlier this month and loved it! I’m now needing a strawberry filling for a cake. Can I use the same recipe and just switch out the fruits? Will the extra juice from the strawberries be too much?

  10. Just made this for my daughter’s bday cake! (she requested vanilla raspberry cake). This was so easy and turned out so yummy!! I modified the recipe due to my lack of ingredients. I didn’t have a fresh lemon so I just used 3 table spoons of store bought lemon juice and only used 2 heaping tablespoons of cornstarch. I think this is the yummiest thing I’ve ever made! Thanks for the recipe!

  11. Amazing recipe!! I did part raspberry, part strawberry. And I used monkfruit instead of sugar. The “jello” consistency was foreign to me, but I gave it a good stir after it sat overnight and it was perfect. Loving the cornstarch slurry. Cannot wait to test out some of your other recipes! Thank you!

  12. I’m so excited to try this! I’m going to use it for a chocolate cake and bloody cupcakes. Did you use this filling for the drip as well? If so how did you get it to the right consistency to come out of the squeeze bottle or is it squeeze-able as is?

Let me know what you think!