Cake:
1/4 cup creamy peanut butter
1 cup water
1/2 cup butter
1 cup sugar
1 cup brown sugar
2 cups flour
1 teaspoon salt
1 teaspoon baking soda
2 eggs
1/2 cup buttermilk
1 teaspoon vanilla
Frosting:
3/4 cup butter
6 Tablespoons buttermilk
1/2 cup peanut butter
3 1/2 cups powdered sugar
1 Tablespoon vanilla
…
Preheat oven to 375. In a medium pot add the peanut butter, water, and butter. Bring to boil, then remove from heat. In the bowl of the kitchen aid mixer, mix together the sugar, brown sugar, flour, salt and baking soda. Add peanut butter mixture. Add eggs, buttermilk, and vanilla. Mix well. Pour into a greased or parchment lined 1/2 sheet pan (12 x 17). Bake for 13-15 minutes.
For the frosting: Bring the butter, buttermilk, and peanut butter to a boil. Remove pan from the heat and add powdered sugar (put through a sieve to avoid lumps) and vanilla. Pour over warm cake.
From the-girl-who-ate-everything.com