2 tablespoons liqueur such as Cognac or Grand Marnier or plain vanilla extract
1/2 cup unsweetened cocoa, sifted
Place chocolate in a bowl.
Bring cream to a boil in a small, heavy saucepan. Pour cream over chocolate.
Let stand for 3 to 5 minutes; gently stir until smooth. Add liqueur and stir to combine.
Cover with plastic wrap and refrigerate until firm, at least 2 hours. Sift cocoa over a baking sheet.
To shape the truffles use one of the following methods:
1. Using a measuring spoon, scoop up 1 teaspoon of chocolate, and roll into a ball about 3/4 inch across. Drop into cocoa; roll each truffle in cocoa to coat.
2. using a pastry bag with a 3/8-inch opening or tip, pipe into mounds (about 3/4 inch high and 1 inch wide) on parchment-lined baking sheets. Freeze until firm, about 15 minutes. Drop into cocoa; roll each truffle in cocoa to coat.
Chill until firm. Store in an airtight container in the refrigerator for up to 2 weeks.