For a make-ahead tip, you can freeze the diced watermelon up to two weeks before the party. Place diced watermelon on a cookie sheet in the freezer for six hours or overnight. Store frozen cubes in a zip-top freezer bag until ready to use.
2 cups diced seeded watermelon, frozen
3/4 cup tequila
1/3 cup triple sec (orange-flavored liqueur)
1 tablespoon sugar
2 tablespoons lime juice
2 cups crushed ice
Granulated sugar (optional)
Lime slices (optional)
Orange slices (optional)
How to Make It
Place frozen watermelon, tequila, triple sec, sugar, and lime juice in a blender; process until smooth. Add ice; process until smooth. Serve in glasses rimmed with sugar, and garnish with lime and orange slices, if desired.