This recipe is from Hugo Ortega’s Street Food of Mexico cookbook. Find several more recipes from the book here.
¾ pound watermelon flesh (about 2 ½ cups), seeded, cut into 1-inch cubes
1 cup granulated sugar
2 teaspoons fresh lime juice
Blend watermelon, sugar, and 1 ½ cups water until smooth, about 2 minutes. Pour into a mesh strainer placed over a large bowl. Press pulp to squeeze out as much liquid as possible. Discard pulp. Transfer liquid to a pitcher, add lime juice, and stir. Serve over ice.