How to Make It
In a pitcher, combine the mezcal, grapefruit juice, elderflower liqueur, lime juice and agave; stir well. Refrigerate until chilled, 1 hour.
Spread the peppercorn sugar on a small plate. Moisten the outer rim of each of 8 martini glasses or coupes with the lime wedge and coat lightly with the peppercorn sugar.
Fill a cocktail shaker with ice. Working in batches and adding fresh ice, shake well and strain the drink into the prepared martini glasses.