Preheat oven to 350 degrees.
Spray 24 mini muffin tins with cooking spray
Mix brownies according to package directions.
Pour 1 TBSP of batter into each tin.
Bake 8-10 minutes.
Immediately press down the tops with the back of a spoon until even and run a knife around the edges.
Let cook for 5 minutes before removing from the tin onto a cooling rack.
In a large bowl cream together cream cheese, butter and vanilla together.
Slowly add in powdered sugar and mix well.
Add in milk if needed to thin out the consistency a bit.
Spread or pipe frosting onto each cooled brownie bite and top with three blueberries.
Store in an airtight container in the refrigerator.