Banana Upside Down Cake

9 1/2 tablespoons butter
1/2 cup brown sugar
1 1/2 cups granulated sugar
1 cup bananas, mashed
2 eggs
1 tablespoon vanilla extract
1/4 cup dark rum
2 cups flour
1 teaspoon baking soda
1/2 teaspoon salt
1 teaspoon ground cinnamon
1/2 teaspoon nutmeg
1/4 teaspoon ground ginger
1/2 cup sour cream
2 large bananas, unripe, cut into 1/3 inch slices
1 1/4 cups walnuts, broken


Preheat oven to 350 degrees. In a 10-inch ovenproof skillet, melt 5 1/2 tablespoon of the butter with the brown sugar over very low heat. Meanwhile, in a large mixing bowl, cream the remaining 4 tablespoons of butter with the white sugar until light. Add the mashed bananas, eggs, vanilla and rum; stir. Then add the flour, baking soda, salt and spices; beat in sour cream. Arrange the banana slices in a pretty pattern in the skillet with the brown sugar mixture; top with the walnuts. Pour the batter over all and place in the oven for 50 to 60 minutes or until a toothpick inserted in the center comes out clean. Turn out immediately onto a plate. Serve with ice cream if you are feeling especially sinful.