• Heat oven to 350° F. Cover an 8-inch baking pan with foil and spray with baking spray.
• Add Betty Crocker Reese’s Peanut Butter & Chocolate Chunk Cookie Mix, butter, oil, eggs and water to a medium-sized mixing bowl, mix with a spatula until combined.
• Pour batter and into the baking pan and spread evenly with a rubber spatula. Bake for 18 to 20 minutes or until a toothpick inserted into the center comes out clean. Set pan aside for about 5 to 10 minutes. Then, lift the foil out of the baking pan to remove the cake and allow to cool completely on a baking rack.

To make the frosting

• Add peanut butter and butter to a large mixing bowl or to a stand mixer bowl. Mix with beater attachment with a stand mixer or an electric mixer until smooth. Add vanilla extract and mix until combined. Add confectioner’s sugar and mix. The consistency will be crumbly looking. Add milk, gradually, one tablespoon at a time and mix until smooth and creamy. Refrigerate frosting when not in use.
• Using an offset spatula, add frosting to the top of the cake. Top with mini chocolate chips. Cut into squares and serve.