This blackberry cake filling is bright yet earthy, the perfect amount of sweet-tart, and ideal to pair with a variety of cake flavors (my favorites are listed below)! It comes together easily with simple ingredients and ends up a nice, thick consistency for filling cakes. It can also be made with fresh or frozen blackberries so you can enjoy it all year long!
Blackberry Cake Filling Ingredients
- Fresh or frozen blackberries. If you have fresh blackberries available, great. Frozen blackberries are more readily available year-round and they work wonderfully in this recipe as well.
- Lemon zest + juice. A little lemon zest and juice compliment the blackberry flavor beautifully.
- Brown sugar. This sweetens the blackberry cake filling just enough so that you still have the perfect amount of tartness.
- Cornstarch. This thickens the blackberry mixture into the perfect cake filling consistency.
- Cinnamon + salt. I love a little cinnamon to compliment the blackberry flavor and add to the earthiness, and a small pinch of salt helps balance everything.
How to Make Blackberry Cake Filling
This blackberry cake filling is so simple to make and comes together in about 20 minutes. It will need to cool for another 30+ minutes after making, so be sure to plan for that in your cake decorating timeline!
Step 1: Add all the ingredients into a small saucepan. Set the saucepan over medium heat and use a silicone spatula to coat the blackberries with the rest of the ingredients.
Step 2: Bring to a boil. The berries will begin to release their juices as you cook them. Once the mixture begins boiling, mash up the berries slightly with your spatula or a fork.
Step 3: Simmer and reduce. Lower the heat after the mixture begins to boil, then simmer for about 10-15 minutes, until the puree has thickened and reduced by about ⅓.
Step 4: Cool. Place the blackberry puree into an airtight container in the refrigerator and allow it to cool for at least 30 minutes, until room temperature or colder, before using as a cake filling. It will thicken as it cools.
How to Fill a Cake with Blackberry Cake Filling
This blackberry cake filling is thick and jam-like, but not thick enough to support a layer cake on its own. To make it more stable, you’ll need to build a buttercream dam around the edge of each cake layer before filling in the center with the raspberry filling. Buttercream is thick enough to support the weight of cake layers in the filling and stacking process. Whipped ganache also works great as a dam if that’s what you’re using to frost the cake.
To build the dam, fill a piping bag with buttercream or whipped ganache and snip off about ½ inch opening on the end. Place the first cake layer on your turntable and pipe a ring around the edge about ¼ inch inward from the edge of the layer. Then, fill in the center with blackberry filling and smooth it down until it’s level with the top of the buttercream dam or just slightly below.
Add the next cake layer on top and repeat the process of filling and stacking until you have one cake layer left. Place that final cake layer upside down on top of the filling so that the bottom of the layer becomes the top of the cake.
This process of filling and stacking the cake with a buttercream dam makes the cake with a soft filling like this much more stable, helping to prevent the filling from oozing out or bulging.
Cake Flavors to Pair with Blackberry Cake Filling
Here are some cake recipes from my blog that will pair amazingly with this blackberry cake filling:
- Blackberry Crisp Cake
- Blackberry Lavender Cake
- Lemon Layer Cake
- Chai Layer Cake
- London Fog Cake
- Bakery-Style White Cake
- One-Bowl Chocolate Cake
You could also use it to make blackberry buttercream, fold it into no-churn ice cream, or swirl it into cake batter! This recipe is super versatile. Let me know if you make it and what you paired it with in the comments below (don’t forget to rate it!) and feel free to tag @sugarandsparrowco on Instagram to show me a photo. I love to see what you create with my recipes!
Blackberry Cake Filling
Ingredients
- 5 Oz (1 ¼ Cups, 142g) fresh or frozen blackberries
- 1/2 tsp lemon zest
- 1 tsp lemon juice
- 1 1/2 tsp packed brown sugar light or dark
- 1 tsp cornstarch
- 1/8 tsp ground cinnamon
- 1/8 tsp salt
Instructions
- Add the blackberries, lemon zest, lemon juice, brown sugar, cornstarch, cinnamon, and salt into a medium saucepan. Cook over high heat until the mixture begins to boil, then use a fork to mash up the berries. Continue to cook for 10-15 minutes or until the puree has thickened and reduced by about 1/3. You should have around 1/2 Cup of blackberry puree after the reduction. Remove from the heat and place into an airtight container in the refrigerator to let cool for about 30 minutes, until room temperature or colder. It will thicken as it cools.
- When the blackberry filling has cooled and thickened, you're ready to use it as a cake or cupcake filling! If you're using it to fill a cake, be sure to pipe a buttercream dam around the edge of your cake layer before filling in the center with this blackberry filling. This way it won't squish out from between your cake layers. This blog post has more details on the filling process.
My daughter doesn’t like chunky bits, can the puree be strained to remove the seeds? If so would the recipe need to be increased to have enough puree for the cake and filling?
Hi April! Yes you can strain out the seeds. I would recommend doubling the recipe, but reserving the cornstarch. Follow the instructions for this seedless raspberry cake filling for the technique: https://sugarandsparrow.com/seedless-raspberry-cake-filling/ and add the cornstarch mixed with an equal amount of water after straining the seeds out. Mix it into the strained blackberry mixture and continue cooking for a few minutes, until the blackberry filling coats the back of the spatula. Hope that helps!