Preheat oven to 350°F. Spray an 11x7 or a 9x13 pan with nonstick cooking spray. Whisk eggs, applesauce, brown sugar, and vanilla until smooth. Stir in cinnamon, salt, and baking powder. Stir in oats and milk. Gently fold in blueberries. Spread in prepared pan. Bake for 28-34 minutes until oatmeal is browned and not jiggly in the center. Cool slightly before serving. Serve with syrup and/or fruit or vanilla yogurt. Store in refrigerator up to 2 days. You can also portion and freeze for quick morning breakfasts!