Preheat oven to 350F degrees. Spray a 9x13-inch baking pan with nonstick cooking spray.
In a bowl, combine 15.25 ounce box yellow cake mix, 1 1/4 cups water, 1/4 cup vegetable oil, 3 large eggs and 1 cup creamy peanut butter. Stir until combined well.
Pour batter into prepared baking dish and bake for about 23-28 minutes.
A toothpick inserted into the middle of the cake should come out clean when cake is done. Allow cake to cool completely before frosting.
In a medium bowl, combine 1 tub chocolate frosting with 1/4 cup creamy peanut butter. Stir until combined.
Spread frosting onto cooled cake.
Place 5-6 Nutter Butter cookies (more if you like lots of cookies) into a ziploc bag. And crush the cookies using a heavy object like a rolling pin. Sprinkle crushed cookies onto cake.