Set up and heat a double boiler.
Add chocolate chips to the bowl of the double boiler.
Stir to melt until smooth.
Fill each cavity of the mold about half full.
Using a spoon, push the chocolate up the sides of the mold, until completely coated.
In the center of each mold, place two teaspoons of peanut butter.
Top off each of the molds with chocolate until full and level.
Place the filled mold in the fridge for at least 4 hours, but better overnight.
When chocolate is completely cooled through, pop the chocolates out of the mold, place in a storage container and keep in the refrigerator until ready to eat.