Preheat oven to 350º. Spray 13x9-inch baking pan with nonstick cooking spray; lightly coat with flour.
Combine 1/2 cup cake mix and oats in small bowl. Cut in margarine until mixture resembles coarse crumbs; set aside.
Place 1 1/2 cups sliced strawberries and 2 tablespoons water in blender or food processor. Process until smooth. Transfer to a small bowl and stir in 3/4 cup diced strawberries. Set aside.
Place remaining cake mix in large bowl. Add 3/4 cup water, egg whites, applesauce cinnamon and nutmeg. Blend 30 seconds at low speed or just until moistened. Beat at medium speed 2 minutes. Pour batter into prepared pan.
Spoon strawberry mixture evenly over batter, spreading lightly. Sprinkle evenly with oat mixture.
Bake 31 to 34 minutes or until wooden pick inserted into center comes out clean. Cool completely in pan on wire rack. Cut into desired size squares.