Watermelon Agua Fresca

4 cups cubed seeded watermelon

½ cup water

½ cup white sugar, or to taste

4 slices lime

24 fresh mint leaves

ice

Puree the watermelon and water in a blender until smooth. Add sugar to taste. Cut the lime slices in half. Place a half lime slice into each of 8 glasses along with 3 mint leaves. Crush with a cocktail muddler, then fill each glass with ice. Pour in the watermelon agua fresca, and stir before serving.