Directions

1. In a mixing bowl, cream together the 1/2 cup butter or margarine, 1 cup peanut butter, and sugar. Beat in the eggs. Stir in the water and vanilla.
2. In a large bowl, whisk together the flour, baking powder, salt, and dry milk. Mix in peanut butter mixture. Pour batter into a greased and floured 10 x 15 inch jelly roll pan
3. Bake for 30 minutes at 350 degrees F (175 degrees C). Cool.
4. To Make Frosting: Cream together 1/4 cup butter or margarine and 3/4 cup peanut butter. Beat in confectioners' sugar. Milk may be added to thin the icing, if needed. Frost the cake. Cut into strips to serve.