In a medium mixing bowl, add the strawberry gelatin mix. Pour the boiling water over it and whisk for 2 minutes, or until the gelatin is fully dissolved.
Stir in the cold water and mix until combined. Let the mixture cool for 5 to 10 minutes so it is warm, not hot.
Whisk in the sweetened condensed milk until smooth. Fold in the whipped topping gently until the mixture is evenly blended and pale pink.
Pour the pink gelatin mixture into an 8-inch square dish or a lightly greased gelatin mold. Smooth the top with a spatula.
Refrigerate for at least 4 hours, or until fully set.
Top with extra whipped topping and halved strawberries if desired. Slice and serve chilled.
