Mix unflavored gelatine and sugar in medium microwaveable bowl until well blended. Stir in soda. Let stand 3 min. or until gelatine is softened. Microwave on High 3 min. or until gelatine and sugar are dissolved, stirring after each minute. Pour into 8-inch square dish sprayed with cooking spray.
Refrigerate 25 to 30 min. or until set but not firm. Meanwhile, add boiling water to raspberry gelatin mixes in medium bowl; stir 2 min. until completely dissolved. Stir in cold water. Cool 15 min.
Pour raspberry gelatin gently over clear gelatine layer in dish. Refrigerate 1 hour or until firm. Cut into 36 squares; top with raspberries just before serving.
Reduced Sugar Version: Save 25 calories and 7g of sugar per serving by preparing with diet carbonated lemon-lime soda and 2 pkg. (0.3 oz. each) JELL-O Raspberry Flavor Sugar Free Gelatin, and substituting 1 Tbsp. granulated sugar substitute for the 2 Tbsp. granulated sugar.
Adults Only: Substitute raspberry-flavored liqueur for the cold water.