In a medium saucepan, combine 1 cup of fresh or frozen blueberries with ¼ cup of granulated sugar. Heat over medium heat for about 10 minutes, stirring occasionally, until the blueberries begin to break down and release their juices.

Once the blueberries are softened, remove the saucepan from heat. Add in ½ cup of unsalted butter, 2 tablespoons of fresh lemon juice, and 1 teaspoon of pure vanilla extract. Stir until well incorporated.

Transfer the mixture to a large mixing bowl. Use an electric mixer on medium speed to whip for about 3-4 minutes until light and fluffy.

If desired, refrigerate the whipped butter in an airtight container for about 30 minutes to 1 hour to thicken for a delightful texture.