Preheat oven to 350°F.
Combine flour, baking powder and salt; set aside.
Beat together 1/4 cup of the butter and the granulated sugar in large bowl until light and fluffy.
Blend in egg.
Add flour mixture alternately with milk, beating well after each addition.
Blend in vanilla.
Melt the remaining 1/4 cup butter in 9-inch ovenproof skillet or 9-inch cake pan.
Stir in brown sugar; spread to cover bottom of skillet.
Cover with pineapple.
Reserve a few cherries for garnish, if desired.
Spoon remaining cherries over pineapple; top with batter.
Bake 50 minutes or until wooden pick inserted in center comes out clean.
Cool in pan on wire rack 10 minutes.
Loosen edges and turn upside down onto cake plate.
Garnish with reserved cherries and mint, if desired.