Take 2 paper muffin cases, put one inside the other.
Cover the bottom of the muffin case with a layer of chocolate chips. Put into microwave for a few seconds until the chips melt (watch it carefully because they burn if left in there too long!) Take out of microwave and add a tablespoon of peanut butter, return to microwave again for a few seconds. Stir in more chocolate chips (as many as you want!).
Freeze until firm.