I tried these using a few different types of chocolate, including good quality truffles. While the truffles still worked, they also liquefied completely and some of the chocolate leaked out of the dough during baking. I recommend using a thick chocolate like a Hershey's Kiss -- you can fit two in there if you put them back to back. {I used Hershey's Chocolate Eggs leftover from Easter and they worked well.} Feel free to experiment with your favorite chocolates!