Prepare simple syrup by mixing equal parts granulated sugar and hot water and stirring until the sugar dissolve. If you don’t have a serrano pepper, any other hot pepper will do – or try some hot pepper flakes instead.
Ingredients:
1/2 seeded and chopped serrano chile (about 1 Tbsp.) 1/2 cup simple syrup, or to taste 3 cups cubed seedless watermelon 3/4 cup tequila reposado 1 (12 oz.) can plain seltzer water Garnish: salt for rim, chile slices, and watermelon wedges
Preparation:
Stir serrano chile into warm (freshly made) simple syrup. Cover and steep 30 minutes. Pour mixture through a fine mesh strainer into a bowl; discard solids. Cool to room temperature, 1 hour.
While syrup cools, process cubed seedless watermelon in a blender until smooth, 2 to 3 minutes. Working in batches, pour watermelon puree through a fine mesh strainer into a bowl; discard solids.
Pour watermelon juice into a 2- to 3-qt. pitcher. Stir in tequila reposado, seltzer and cooled syrup. Salt the rims of 8 Collins glasses and fill with ice. Pour cocktail evenly into glasses; garnish with chile slices and watermelon wedges