Combine watermelon, sugar, lime juice and 1 cup ice in blender until smooth.
Serve immediately.
Notes
Use a seedless watermelon. No one wants to pick out those black seeds by hand! Be sure to use a seedless watermelon to ensure a smooth, frosty consistency.
Mix it up. Swap out the lime for lemon juice or ginger for a zesty kick of flavor, or add a handful of fresh mint or basil.
Make it boozy for grown-ups. Add a shot of vodka, rum or tequila for an adult-twist.
Add some bubbles. Finish each glass with sparkling water or club soda for a fizzy finish.
Elevate your slushie. Add a simple garnish such as a mint sprig and a lime wedge, making it bar-quality!
Try watermelon ice cubes. To keep the flavor 100% purely watermelon, blend and freeze watermelon juice into ice cubes beforehand, using the watermelon ice instead of plain ice cubes.