Ingredients
1/3 cup sugar
Peeled zest of 2 limes, plus 1/3 cup fresh lime juice, plus lime wedges for making salt rim, plus thinly sliced rounds for serving (optional)
1/2 small seedless yellow watermelon (about 2 1/2 pounds), peeled and cut into cubes (about 6 cups)
6 ounces tequila blanco
1 ounce elderflower liqueur, such as St. Germain
Coarse salt or Himalayan pink salt, for glasses
Preparation
Bring sugar, 1/3 cup water, and lime peels to a boil, stirring, until sugar has dissolved. Remove from heat; let cool completely. Strain into a pitcher with lime juice.
Working in batches, purée watermelon in a food processor or blender; strain through a coarse-mesh sieve (you should have 3 cups). Add melon purée, tequila, and elderflower liqueur to the pitcher with lime syrup and stir. Chill, covered, at least 2 hours and up to 2 days.
When ready to serve, run a lime wedge around the rim of each glass and dip glasses in coarse salt. Fill glasses with ice and 1 or 2 thin lime rounds. To make each drink, add more ice and 1/2 cup tequila mixture to a cocktail shaker. Shake 15 seconds; strain into a glass. Repeat for remaining drinks and serve immediately.
