I saw this recipe on a blog called sixsistersstuff.com. When I saw the picture, I had to try it. They are very good and make a lot, so you may want to serve them at a large dinner, or you may be left with tempting leftovers. My guests loved them!
1Cream sugars and butter together. Add the vanilla, eggs, and peanut butter and combine. Add the remaining ingredients and mix together. Spread dough on a greased jelly roll pan (18x13x1"). Bake at 350 degrees F for 15 minutes (until golden brown). While hot, spread 1 1/2 cups peanut butter on top. Cool so that the peanut butter has become solid again. (They can be put in the fridge so they set up faster). Spread your favorite chocolate frosting on top and cut into bars.
2Here is the recipe for frosting, given by the contributer on the blog.
1 stick (1/2 cup) margarine, softened
1/4 cup milk
1-2 tsp vanilla (depending on your taste)
3 T cocoa
2-3 cups of powdered sugar
Mix all ingredients with a mixer until smooth and spread on top of bars.