In medium saucepan, combine semisweet chocolate, bittersweet chocolate and half-and-half. Cook over low heat until chocolate is melted, stirring frequently. Remove from heat. Cool 10 minutes.
With wire whisk, beat butter, 1 tablespoon at a time, into chocolate until smooth and creamy. Beat in cherries and liqueur. Cover; refrigerate 1 1/2 hours, stirring twice, or until mixture is thick and can be molded.
Spread grated baking bar on sheet of waxed paper. Drop teaspoonfuls of chocolate mixture over grated baking bar; roll each to coat and shape into rough ball. For variety, roll some of the chocolate mixture in cocoa. Place truffles in candy cups. Refrigerate until serving time.