Love these guys. I do mine a little different though. I melt the chocolate chips in the microwave and I also use nilla wafers instead of Graham crackers. I also pipe the chocolate in the cups. It's much easier to handle when you co it that way I think. After I've melted the peanut butter and added the wafers I out that in the fridge and let it harden slightly and roll into balls that I then place on the piped chocolate. Same result but much less time consuming.
These are SO GOOD! I could not find Nestle bars so I used Hershey's. I also do not own a double boiler, so I melted the chocolate and peanut butter in glass bowls over pans of hot water. I would recommend putting just enough chocolate to cover the bottom of the liner, then the peanut butter and more chocolate so that there is enough space left to cover the peanut butter completely with chocolate. I got 21 mini peanut butter cups out of this amount of chocolate, but had quite a bit of peanut butter left over. Very yummy recipe! Made for PAC Spring '09