Instructions

1 Preheat oven to 325 degrees F (165 degrees C). Grease and flour a 10 inch tube pan. Sift together the flour, baking powder, baking soda and salt. Set aside.

2 In a large bowl, cream together 1 cup butter, 1 1/2 cups white sugar and 1/2 cup brown sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla. Beat in the flour mixture alternately with the sour cream, mixing just until incorporated.

3 Pour batter into prepared pan. Bake in the preheated oven for 75 minutes, or until a toothpick inserted into the center of the cake comes out clean. Remove cake from oven and immediately prick cake all over with a wooden pick 20 to 30 times. Pour butter sauce over cake. Allow cake to cool completely as cake is very fragile when warm. Run a knife around the edges of the pan and invert cooled cake onto a serving dish. Dust with powdered sugar.

4 To make the Butter Sauce: Heat 1 cup sugar, 1/2 cup butter, 1/4 cup water and 1 tablespoon vanilla over medium heat until sugar dissolves, about 10 minutes. Do not boil.