Preheat oven to 325 degrees. Place 3 T butter in a 9 inchx11- half inchx2 inch cake pan. Place in oven until melted. Remove pan from oven, swirl butter to coat pan, and immediately sprinkle brown sugar evenly over bottom of pan. Arrange pineapple slices in single layer over the brown sugar. Beat together 4 T butter and sugar in medium-size bowl with an electric mixer on high-speed until creamy. Beat in egg, molasses and milk until well blended. Stir together flour, baking soda, cinnamon, ginger and salt in a medium-sized bowl. Beat into batter on low-speed, mixing until incorporated. Spoon evenly over the pineapple in baking pan. Bake for 60 minutes or until cake tester inserted near center comes out clean. Remove from oven and immediately turn out onto serving platter. Garnish the center of each pineapple ring with a maraschino cherry half.