Bake cake according to box. After the cake is done baking, let cool thoroughly before icing. In a bowl, mix the room temp cream cheese with the powdered sugar. You can add more powdered sugar to taste if you want. So check out the flavor and see. (Some people like a more peanut butter taste and some prefer sweeter)If you want sweeter, go two cups.
After they are mixed together, microwave your desired amount of creamy peanut butter for about 25 seconds. Add into cream cheese and powdered sugar mixture.
Finally, add in vanilla extract and mix until smooth and shiny looking. Place in fridge so that it becomes spreadable. About five minutes.
Frost your cake as you would like and then add Hershey's chocolate syrup in the design you would like. Eat and ENJOY!
P.S. With these measurements you may have quite a bit of frosting left over. Save and dip fruit in it if you would like or even pretzels!