1Preheat oven to 350f. Grease and flour tow 10inch pans. Bake cake according to directions and pour into prepared pans.
2Bake cake until spring bake when touched about 40 minutes. Allow cake to cool completely in pan. Cut cakes vertically so that you have four bars.
3For Peanut Butter Filling,cream the butter, cream cheese, and peanut butter together until smooth. Gradually add confectioners' sugar 1 cup at a time until combined and sweet to taste. Add vanilla.
4Chocolate Butter Cream frosting
In saucepan combine sugar with enough water to moisten. Bring to a boil, washing down sides as you go with a brush. Bring to 240F.
5As sugar is cooking begin whipping the egg whites. Increase speed as eggs gets closer to a soft peak. Mix the butter and shortening, salt together in a seperate bowl. When sugar reaches tempt pour into whipped egg whites.
6Continue to whip until mixing bowl is warm to touch. Quickly add butter mixture. Whip for 5 mintues until buttercream comes together and is smooth. Add melted chocolate and cocoa. Whip until combined. Store brand frosting may be used.