Melt butter in saucepan and add brown sugar. Cook over low flame until well blended. Remove from heat. Drain the juice from the pineapple and save, then stir crushed pineapple into the sugar mixture.
Divide the topping equally into the bottom of each greased muffin cups and add a maraschino cherry half (if desired)
To prepare the batter:
Cream the butter, add the sugar and beat until fluffy.
Beat egg yolk mixture. Sift the flour and baking powder together; add alternately with the pineapple juice. Add vanilla. Beat the egg white until stiff and fold into the batter
Pour this batter over the topping and bake.
Cool , then turn cupcakes carefully onto a cake plate, pineapple side up.