Try different types of nuts with different types of liqueurs. I made them without nuts and only with rum, because that's what I had on hand at the time.
Cover and chill for about 1 hour.
Place about 1-inch (2.5 cm) apart on ungreased baking sheets.
This can take 1 or 2 minute zaps in the microwave.
You can also melt the chocolate and butter in a double boiler over simmering water.