Preheat oven to 350 degrees. Put all sponge cake batter ingredients in an mixing bowl and beat together with a wire whisk, set aside.
In a 9 inch cast iron skillet, melt butter and brown sugar together and simmer until it foams. Place pineapple rings on top to form a circle with one in the middle. Place a cherry in each center and sprinkle with chopped walnuts (or any nut u want to use) Pour sponge cake batter over pineapple rings. Bae for 30 minutes or until cake tests done. Let set for 10 minutes, loosen edges and invert on a serving plate. Serve warm or cold, plain or with vanilla ice cream or whip cream. Enjoy!