Gooey Peanut Butter Cake
["1 pkg. chocolate cake mix", "1 egg", "8 Tbsp. butter, melted"]
["Preheat oven to 350\u00b0. Combine the cake mix, egg, and butter and mix well. Pat into a lightly greased 13 x 9 inch baking pan. Prepare filling."]
["chocolate cake mix", "egg", "butter"]