This blueberry cake filling is thick and bursting with blueberry flavor. It's perfect for filling cakes, pies, cupcakes, tarts, and more! It's easy to make with 3 simple ingredients in under 20 minutes.
Add frozen blueberries, sugar, and lemon juice to a saucepan over medium-low heat. Cook for 7-10 minutes while gently stirring until the sugar melts and the blueberries release their juices.
Bring the mixture to a simmer and mix constantly for 10 more minutes. Mash the softened berries with your spatula or a fork.
Bring to a boil. Once the filling starts boiling, immediately take it off the heat and pour into a heat-proof bowl or jar.
Cool to room temperature, then chill in the refrigerator for 1-2 hours before using in your baked goods.
Notes
Storage: Store in an airtight container in the refrigerator for up to 4 days.Freezing: Transfer to a freezer-safe, sealed container. Freeze for up to 3 months. Thaw in the refrigerator overnight before using.