Combine unflavored gelatine and sugar in medium size microwave safe bowl. Add 2 cups 7Up, stir until combined. Let set for 3 minutes or until gelatine is softened. Stir and place in microwave on high for 3 minutes, stirring after each minute, or until gelatine and sugar are completely dissolved.
Pour sparkling gelatine mixture into an 8"x8" baking pan sprayed with non-stick cooking spray.
Place in the refrigerator for 25-30 min, until set but not firm.
Meanwhile, add unprepared berry blue gelatin mixes to a separate medium bowl. Pour boiling water into bowl. Stir until completely dissolved, about 2 minutes. Stir in remaining 1/4 cup 7Up. Allow to cool for 15 min.
Pour sparkling berry blue gelatin gently over clear gelatine layer in dish.
Refrigerate until firm, about 1 hour.
Cut into 36 squares. Serve and enjoy!
Notes
You can substitute any flavor to make these to match for any party.
Recipe adapted from Kraft