Description

This vibrant raspberry cake filling is a luscious, homemade fruit compote that brings a fresh, tangy sweetness to layer cakes and cupcakes. Made with fresh or frozen raspberries, cornstarch for thickening, and enhanced with lemon juice and vanilla, it’s easy to prepare and perfect for adding a burst of natural fruit flavor to your desserts. The filling thickens as it chills, creating a stable, spreadable consistency that pairs beautifully with buttercream frosting for a professional finish.

Ingredients

Scale

Raspberry Filling

1.5 Tablespoons (22ml) water
1.5 Tablespoons (4.5 teaspoons or 12g) cornstarch
3 cups (12 ounces/about 340–375g) fresh or frozen raspberries (do not thaw)
1/3 cup (67g) granulated sugar
1 teaspoon lemon juice
1/2 teaspoon pure vanilla extract

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Instructions

Mix Cornstarch and Water: Whisk the cornstarch and water together until the cornstarch is completely dissolved. A fork works well for this easy mixing step.
Cook Raspberry Mixture: Combine the cornstarch mixture with the raspberries (no need to thaw if frozen), granulated sugar, and lemon juice in a medium saucepan over medium heat. Stir constantly with a silicone spatula, mashing the raspberries as they soften.
Boil Filling: Bring the mixture to a boil and allow it to boil for 5 full minutes, stirring occasionally to prevent burning. Then remove from heat and stir in the vanilla extract.
Cool and Refrigerate: Let the filling cool at room temperature for 10–15 minutes. Transfer it to a container and refrigerate for at least 4 hours, or up to 1 week for best flavor and texture, covering tightly if chilled longer than 4 hours.
Fill Cakes: Use the cooled filling between cake layers for 2- or 3-layer cakes. Start with a thin buttercream base layer and pipe a buttercream dam to keep the filling contained. Spread about half a cup for 3-layer cakes or 3/4 cup for 2-layer cakes inside the dam. Assemble layers and repeat if needed.
Fill Cupcakes: Cut out a cone-shaped center in cooled cupcakes and fill the cavity with 1 to 2 teaspoons of raspberry filling. Replace the cupcake top and gently press to seal. This recipe fills about 2 dozen cupcakes.
Storage: Cakes or cupcakes with raspberry filling and buttercream can be covered and kept at room temperature for 1 day. After that, store in the refrigerator to maintain freshness.

Notes

The raspberry filling thickens further as it chills, so ensure it is completely cooled before use.
If refrigerating longer than 4 hours, cover the filling tightly to prevent drying out.
Buttercream frosting acts as a crucial barrier to keep the filling from seeping and to stabilize the cake layers.
For freezing instructions, consult additional notes or recipes specific to freezing fruit fillings.
This filling pairs best with buttercream for structural integrity in layered cakes.
Adjust filling amounts based on cake size: roughly 1/2 cup per layer for 3-layer cakes, 3/4 cup total for 2-layer cakes.