Peanut Butter Frosting

http://www.lynnskitchenadventures.com/2009/03/peanut-butter-sheet-cake.html

The link above gives you the recipe for a peanut butter sheet cake with peanut butter frosting, but we like a white or chocolate cake (or banana bread) with peanut butter frosting better.

1/2 cup butter
2/3 cups creamy peanut butter
6 tablespoons milk
2 1/2 cups powdered sugar
1 teaspoon vanilla

Combine the butter, peanut butter, and milk in a saucepan. Bring to a boil stirring constantly. Add the powdered sugar and the vanilla. Mix well. It will be thick. Pour over cake while both are still warm. My frosting did drip over the sides a little, so pour and spread slowly. Let cool, slice, and serve.