to avoid this, mix in blueberries at the very end of the mixing process, and use a wide, flexible spatula to gently fold them in. if your recipe has you mixing your batter with an electric mixer, mix it fully, then add the blueberries in by hand.
if you have a favorite muffin recipe that uses fresh fruit—it’s easy to substitute blueberries instead. for other berries, you can substitute in equal quantities. for larger fruits, try to think of things in terms of volume. if 1 peach gives you about 3/4 cup chopped fruit, then sub in 3/4 cup blueberries to replace it. or just wing it—there’s no such thing as 