Ingredients 1 cup cubed seeded watermelon 1 1/4 cups water 3 tablespoons sweetened strawberry lemonade drink mix Check All Add to Shopping List Directions Place the watermelon pieces onto a plastic-wrapped baking sheet, and freeze until solid, about 45 minutes. Place the frozen watermelon, water, and strawberry lemonade drink mix in a blender; blend until slushy.