Preheat oven to 350 degrees. In a large bowl, combine oats, brown sugar, baking powder, salt and cinnamon. Combine eggs, milk and butter; add to the dry ingredients. Stir in apple, peaches and blueberries.
Pour into an 8-in. square baking dish coated with cooking spray. Bake, uncover, until a knife inserted in center comes out clean, 35-40 minutes. Cut into squares. Serve with milk if desired.