Peanut Butter Crunch Cake
["yellow cake mix", "1 c. peanut butter", "1/2 c. brown sugar", "1/4 c. oil", "1 c. water", "3 eggs", "1/3 c. nuts (optional)"]
["Mix the first 3 ingredients and reserve 2/3 cup for topping (add nuts; optional).", "Add oil, water and eggs to remaining batter and beat.", "Sprinkle topping over batter and top with chocolate chips.", "Bake at 350\u00b0 for 40 to 45 minutes.", "Use a 9 x 13-inch pan."]
["yellow cake", "peanut butter", "brown sugar", "oil", "water", "eggs", "nuts"]