Cream butter; gradually add brown sugar, beating until light and fluffy. Spread creamed mixture evenly in a 9-inch cast-iron skillet. Arrange pineapple slices and cherries evenly over creamed mixture.
Beat egg yolks until thick and lemon colored. Gradually add sugar, beating well. Combine flour and salt; add to yolk mixture alternately with water, stirring well after each addition. Stir in vanilla.
Beat egg whites (at room temperature) until stiff peaks form: fold into batter.
Spoon batter evenly over pineapple slices in skillet. Bake at 350° for 50 minutes or until wooden pick inserted in center comes out clean. Cool 30 minutes in pan, and invert cake onto serving plate.
Oxmoor House Homestyle Recipes