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 pretty detailed, so I wanted to make a post sharing just the raspberry filling.

I also hope this will encourage people to get creative and add this filling to their favorite cake and cupcake recipes.

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.

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.

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.

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 of concentrated raspberry seeds, which can be composted.

Frozen vs. Fresh Raspberries

I tested 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.

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 ever 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.

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.

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 use a fresh lemon! Pre-squeezed lemon juice doesn’t have the same effect.

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

The lemon really just adds 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 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.

This raspberry cake filling can be stored in the freezer for 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.

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.

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