Learn how to make Raspberry Filling for Cupcakes with just four simple ingredients, perfect for adding a fresh, fruity layer to cakes, donuts, cookies, and more!
In a medium saucepan, add the raspberries, sugar, and lemon juice. Stir well to combine the ingredients. Begin by adding 3 tablespoons of sugar to the raspberries, then gradually add more as needed to adjust the sweetness to your taste.
Place the saucepan over medium heat and cook the mixture, stirring occasionally. The raspberries will soften and start to break down as they heat. This should take about 3-4 minutes.
Sprinkle the cornstarch evenly over the mixture and stir continuously to avoid lumps. Cook for another 2-3 minutes until the filling thickens. You’ll know it’s ready when it coats the back of a spoon.
Once the filling reaches your desired thickness, remove it from the heat and let it cool completely before using. For best results, cover the filling with cling wrap touching the surface to prevent a skin from forming.
Notes
Both fresh and frozen raspberries work well. If using frozen, there's no need to thaw them before adding them to the saucepan.
Taste your filling as it cooks. Depending on the sweetness of the raspberries, you can adjust the amount of sugar.
The filling thickens as it cools. If using it as a cake filling, make sure it is thick enough so it doesn’t bleed through the layers. For a smoother, glaze-like consistency, blend the mixture and strain out the seeds.
Store the filling in an airtight container in the refrigerator for up to 1 week. It can also be frozen for up to 3 months.