1/3 cup heavy cream
6 ounces high quality bittersweet chocolate, such as Lindt or Tobler, coarsely chopped
2 tablespoons unsalted butter (at room temperature)
About 1/4 cup cocoa
Bring cream to a boil in a small heavy-bottom saucepan over moderate heat or in a bowl in a microwave. Remove the pan from the heat and add the chocolate and butter, whisking until smooth. Pour the warm chocolate mixture into a shallow bowl and press a piece of plastic wrap directly against the surface. Refrigerate for at least 3 hours.
Using a spoon, scoop 24 rounded teaspoonsful of the cold chocolate mixture onto a sheet of wax paper. Coat your palms with cocoa and roll each mound between your palms to form a ball. Dredge the truffles in the cocoa, tossing them gently from one hand to the other to remove the excess cocoa. Chill the truffles, covered, for at least 2 hours before serving.
Add 2 tablespoons dark rum to the warm chocolate mixture before chilling. Reserve 24 whole Macadamia nuts and finely chop 5 Macadamia nuts. Mold each truffle around a whole Macadamia nut. After dredging the truffles in cocoa, dip the tops in the chopped nuts.
Brandied Apricot Truffles:
Soak 1 rounded cupful finely chopped or diced dried apricots in 1/4 cup brandy in a covered container for at least 1 hour. Add this mixture to the warm chocolate mixture.