P our the cocoa into a pie plate. Line an airtight container with waxed paper. Dip a melon baller or small spoon into a glass of warm water and quickly scrape across the surface of the chilled truffle mixture to form a rough 1-inch ball. Drop the ball into the cocoa. Repeat with the remaining truffle mixture.
G ently shake the pie plate to coat truffles evenly.
Transfer truffles to the prepared container, separating layers with additional waxed paper. Cover tightly and refrigerate up to 2 weeks, or freeze up to 3 months. Preparation L ine a baking sheet with waxed paper. Form the truffles and place on the prepared baking sheet. Freeze, uncovered, at least 2 hours.