Preheat oven to 350 F. Stir together baking powder, baking soda, and salt. Stir in flour. In a separate bowl, mix sugar, banana, applesauce, milk, and flavoring. Add wet into dry ingredients, and mix just until combined. In a bowl or plastic bag, dust berries with extra flour and toss gently to coat. Fold berries very gently into batter. Line 18 cups in muffin tins with paper liners and scoop batter into cups (1/4 to 1/3 cup per muffin), using all the batter. Bake 25 to 30 minutes or until toothpick inserted in the center comes out clean. Cool in tins five minutes, then remove to rack. Serve warm, or let cool completely and store in airtight container in refrigerator.