Coat a 9x1-1/2-inch round cake pan with nonstick cooking spray. Melt the 1 tablespoon butter in the pan by placing the pan in the oven for 5 minutes, while it preheats to 350 degree F. Remove pan from oven. Stir brown sugar and corn syrup into melted butter in pan. Spread evenly in pan. Arrange pineapple and cherries in pan on top of brown-sugar mixture; set aside.
In a small bowl, combine flour and baking powder. In a medium bowl, beat egg whites and egg with an electric mixer on high speed for 4 minutes. Gradually add the granulated sugar, beating until light and fluffy.
Add flour mixture and beat just until combined. In a small saucepan, heat and stir the milk and the 2 tablespoons butter until butter melts. Add to batter, beating until combined. Pour into pan over pineapple.
Bake in a 350 degree F oven for 30 to 35 minutes or until wooden toothpick inserted in center of cake comes out clean. Cool in pan for 5 minutes. Loosen the side and invert cake onto a serving plate. Serve warm. Makes 8 servings.