1. Separate eggs, placing whites in large bowl, yolks in small bowl. Reserve 1/2 cup chocolate pieces. In large glass bowl, place remaining chocolate and the butter. Microwave on HIGH 3 minutes, stirring until well blended. 2. Beat in yolks, one at a time, beating well after each. Let cool, stirring occasionally, 15 minutes, or until slightly thickened. Stir in 4 tablespoons creme de menthe. With electric mixer at high speed, beat egg whites until stiff, moist peaks form. With same beaters, in small bowl, beat cream until stiff. Fold the egg whites and half of whipped cream into the chocolate mixture. Cover; refrigerate mousse and remaining cream until sready to serve. 3. Meanwhile, in small glass bowl, place reserved chocolate. Microwave on HIGH 3 minutes, or until chocolate is melted. On foil lined tray, trace a 6-inch circle. Spread melted chocolate within circle. Refrigerate 45 minutes; with knife, cut circle into 6 equal wedges. 4. To serve: With electric mixer at high speed, beat the reserved whipped cream with the remaining cream de menthe. Spoon into pastry beg fitted with 1/2-inch star tip. Pipe 6 swirls on mousse. Between each swirl, press a chocolate wedge slightly into mousse to stand upright. Garnish with fresh mint, if desired. Makes 10 servings.