For the topping, melt the chocolate and peanut butter together in the microwave for 1 minute. Stir. If not completely melted you can heat in 10 second intervals until smooth. Spread over the top of the peanut butter layer.
1/4 cup peanut butter, 10 oz semi-sweet chocolate
Chill dessert in the refrigerator for about an hour, or in the freezer for 15 minutes. Cut into bars and serve.
You can use a hand mixer or even a blender if you don't have a food processor. We like the food processor because it makes for the smoothest mixture.
This recipe uses semi sweet chocolate for the topping. If you want it a big sweeter, and closer to the flavor of a Reese's Peanut Butter Cup, simply substitute milk chocolate for the semi sweet. I prefer to use baking chocolate, but you can certainly use chocolate chips instead.