Bring 3/4 cup water to a boil and stir water into strawberry gelatin using a whisk until completely dissolved, around 2 minutes
Add 2 cups frozen fruit; stir until gelatin starts to thicken
Mix 1/2 cup of the gelatin mixture into the whipped topping until well blended
Spoon whipped topping mixture evenly into 4 dessert cups and top with remaining gelatin and fruit mixture over whipped topping mixture.
Refrigerate 15 minutes, or until set
Top with whipped topping if desired