Melt butter in a 9-inch cast-iron skillet. Spread brown sugar evenly over bottom of skillet. Drain pineapple, reserving 1/4 cup juice; set juice aside. Arrange pineapple slices in a single layer over brown sugar mixture, and place a cherry in center of each pineapple ring; set skillet aside.
Beat egg yolks at medium speed with an electric mixer until thick and lemon-colored; gradually add granulated sugar, beating well.
Heat reserved pineapple juice in a small saucepan over low heat. Gradually add juice mixture to the yolk mixture, beating until blended.
Combine all-purpose flour, salt, and baking powder; add dry ingredients to the yolk mixture, beating at low speed with electric mixer until blended.
Beat egg whites until stiff peaks form; fold egg whites into batter. Spoon batter evenly over pineapple slices.
Bake at 325° for 45 to 50 minutes. Cool cake in skillet 30 minutes; invert cake onto a serving plate. Serve warm or cold with whipped cream or ice cream, if desired.
Express Pineapple Upside-Down Cake: Follow original recipe directions for first 4 ingredients. Substitute 1 (9-ounce) package golden yellow cake mix for next 5 ingredients. Prepare cake mix according to package directions, substituting 1/2 cup pineapple juice for 1/2 cup water. Spoon batter over prepared pineapple slices as directed. Bake at 350° for 20 to 25 minutes or until a wooden pick inserted in center comes out clean.
Note: For testing purposes only, we used Jiffy Golden Yellow Cake Mix.