COOL WHIP for garnish Stir boiling water into JELL-O in large bowl 2 minutes or until dissolved. Mix cold water and ice to make 1.25 cups. Gradually add to gelatin, stirring until slightly thickened (consistency of unbeaten egg whites). Remove any remaining ice. Stir in tub COOL WHIP with wire whisk until smooth. Refrigerate 10 to 15 minutes or until mixture is very thick and will mound. Spoon into crust. (There is likely to be some left over) Refrigerate 4 hours or until firm. Garnish with a lemon slice, and a dollop of COOL WHIP for each slice, just before serving.