Preheat oven to 375. Prepare muffin cups with cooking spray in a muffin pan or use paper muffin liners.
Mix oat bran and milk. Let stand for 10 minutes.
In a large mixing bowl, mix applesauce, egg, brown sugar, and vanilla. Beat in bran mixture.
Sift together all-purpose flour, whole wheat flour, baking soda, baking powder, and cinnamon. Stir into bran mixture until just blended. Fold in the cup of blueberries. Fill muffin cups about 2/3 full.
Bake for 15 to 20 minutes until a toothpick inserted in the middle comes out clean.
