Combine melted butter and brown sugar and spread the mixture into a 9-inch round pan.
Arrange pineapple slices inside the pan, fill the center, and the empty edges of the pan between the pineapple slices with maraschino cherries. Set aside.
Cream butter and white sugar, then add the egg, milk, and vanilla.
Sift the flour, baking powder, and salt. Add the flour mixture to the liquid ingredients and blend well.
Pour the batter mixture over the prepared pan with pineapple slices.
Bake in the preheated oven for 40-50 minutes or until an inserted toothpick comes out clean.
Invert cake on a serving plate and let set inverted for 3 minutes before removing the pan.