In a 2-quart saucepan, combine the fresh blueberries and granulated sugar over medium heat.
Use a potato masher to break down the blueberries, cooking for 8 to 10 minutes until they have reduced to a thick jam-like paste.
Remove the cooked fruit from heat and allow it to cool to room temperature. Transfer the mixture to a bowl and refrigerate for faster cooling.
In a large mixing bowl, beat together the softened cream cheese and butter until light and fluffy.
Add the vanilla extract and beat until well combined.
Gradually beat in the powdered sugar, one cup at a time, until the frosting is thick and fluffy.
Once the blueberry reduction has cooled, beat it into the frosting until well incorporated.