01 - 
                Preheat the oven to 350°F (175°C) and grease a sheet cake pan.
              
              
              
                02 - 
                In a large mixing bowl, combine the yellow cake mix, eggs, softened butter, creamy peanut butter, and water. Beat the mixture until smooth and well blended.
              
              
              
                03 - 
                Pour the batter evenly into the prepared sheet cake pan and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
              
              
              
                04 - 
                While the cake is baking, beat together the creamy peanut butter and softened butter in a separate bowl until creamy.
              
              
              
                05 - 
                Gradually add the powdered sugar, milk, and vanilla extract to the peanut butter mixture, beating until smooth and spreadable.
              
              
              
                06 - 
                Once the cake is done baking, allow it to cool completely in the pan. Spread the peanut butter frosting generously over the cooled cake.
              
              
              
                07 - 
                Cut the cake into squares and serve.