This dish contains raw eggs. Be advised that raw eggs may cause food poisoning and could be especially hazardous for the elderly, small children, and pregnant women.
Mix by hand. Cream butter with sugar then add egg yolks and finally the rum. Soften the chocolate in a double boiler (don't let the inner pan touch the water in the outer pan) or a microwave.
Combine the melted chocolate with butter mixture, and beat with a spoon for about 5 minutes.
Refrigerate overnight.
Form into balls using a plastic bag as a mitt. Roll the balls in chopped nuts or chocolate sprinkles, powdered sugar, or anything else.
