Mix ingredients together in a microwave safe bowl. Microwave for 3 minutes. Remove from bowl and spread in a 9x6 buttered cake pan. Place in the fridge and allow to cool.
If you use chocolate frosting with the peanut butter you end up with a fudge that tastes like resees peanut butter cups. Once mixture is out of the microwave you can add all sorts of cool things like nuts and or toffees.
ATTENTION: The friend that told us about this recipe is diabetic. His wife makes it for him using sugar free frosting and all natural peanut butter.