A repost from my old baking blog.

4 ounces bittersweet chocolate
4 ounces sweet chocolate
1 cup heavy whipping cream
2 to 3 tablespoons rum, brandy or other spirits
2 teaspoons vanilla extract, optional
Confectioners sugar to taste

Chop or break off chocolates into small chunks. In a microwave-safe bowl or large measuring cup, combine with the whipping cream. Microwave in 15-30 second increments, stirring well after each, until you have a smooth brown mixture. Stir in spirits and/or vanilla. If you need to use it right away, stir briskly in bowl set over ice, until it reaches the consistency you want. Otherwise, keep in refrigerator, covered, up to a week, until needed. Sprinkle or sieve in confectioners sugar and stir well.

Use this as a filling for cakes or for frosting.

To use for making truffles, simply add more chocolate, or use less cream. Chill and form into balls, then coat with cocoa powder, nuts, sprinkles, etc. or coat with a chocolate glaze and decorate with royal icing, etc.