MICROWAVE chocolate and 1 cup cream in large, uncovered, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. If morsels retain some of their original shape, microwave at additional 10- to 15-second intervals, stirring just until smooth. Cool to room temperature.
BEAT remaining 1 cup cream and powdered sugar in chilled medium mixer bowl until stiff peaks form. Carefully fold whipped cream into chocolate mixture until blended. Fold in liqueur. Fill plastic bag with mousse; seal. Cut 1/2-inch from corner of bag. Squeeze bag to pipe into cups.
REFRIGERATE for 1 hour or until firm. Garnish each with a fresh raspberry or mint leaf.
NOTE: For a different flavor, add 1 tablespoon of vanilla extract or mint liqueur into chocolate mixture before spooning into cups.
*Plastic mini bowls or cups can be found in party-supply stores.