peanut butter sheet cake with chocolate icing

Peanut butter +  chocolate =  love.  Is there anyone who does not like peanut butter and chocolate?  If you do don't fight it just give in.  You will fall in love trust me.  Could a couple be more perfectly matched?  Do they ever fight?  They just seem to constantly compliment each other.  A peanut butter sheet cake ... yum!  Poke holes in it and pour a sweet thin chocolate icing all over it so, it fills those holes and makes the perfect little pockets of chocolate icing ... now you got a reason to pump your fist in the air.  My only regret other then I ate one too many pieces of this cake is that I did not go all Paula Deen on this cake.  I am still kicking myself that I did not add a bit of peanut butter to the icing and cut up reese's peanut butter cups on top.  If you are going to do Paula do you really leave a usable calorie behind.  Next time.  Enjoy!

peanut butter sheet cake with chocolate icing
adapted: paula deen

1 cup all-purpose flour
1 cup plus 2 tablespoons sugar
3 1/2 teaspoons baking powder
1 teaspoon salt
2 cups graham cracker crumbs
3/4 cup peanut butter
1/2 cup shortening
1 cup plus 2 tablespoons milk
1 teaspoon vanilla extract
3 eggs

2 cups sugar
2 tablespoons cocoa
8 tablespoons (1 stick) butter
1/2 cup whole milk

Preheat oven to 375 degrees F if baking with a metal dish; 325 degrees F if using a glass dish.
Sift flour, sugar, baking powder, and salt together. Add graham cracker crumbs, peanut butter, shortening, milk, and vanilla. Beat mixture with electric mixer on low until moistened, and then beat on medium for 2 minutes. Add eggs and beat for 1 minute. Bake in greased 9-inch by 13-inch pan for 30 to 35 minutes. Do not remove from pan to cool.
For the frosting: mix all of the ingredients together. Pour into a saucepan and bring mixture to a boil. Boil for 1 minute. Cool slightly. With a wooden spoon handle, poke a few holes in the cake, and then pour the warm frosting over it.