Mold fondant into balls or other shapes with your fingers and let stand overnight on a marble slab, or on waxed paper, until thoroughly hardened. The longer they harden, the better.
Melt the chocolate very slowly in the top of a broiler. When melted, add to it a lump of paraffin about the size of a walnut and a lump of butter half the size of the paraffin. Add a few drops of vanilla.
Keep the water in the lower part of the double boiler boiling to make sure the chocolate remains melted. Dip the fondant balls with tongs into the chocolate. Slip them onto waxed paper at once.