Method

• 1.
  For the rosemary and grapefruit syrup, combine sugar, rosemary, grapefruit zest and 200ml water in a saucepan and bring to the boil. Transfer to a heatproof container and chill until completely cooled (syrup can be stored, covered and chilled, for up to 2 months).

• 2.
  Combine sugar, 1/2 tsp grapefruit zest, rosemary and 2 tbs salt flakes in a shallow dish. Rub rims of serving glasses with a little water or grapefruit flesh, then press rims into salt mixture.
• 3.
  To make the cocktail, combine tequila, pickled chilli liquid, 200ml rosemary and grapefruit syrup, grapefruit juice and remaining zest in a large jug. Transfer one-fifth tequila mixture and some crushed ice to a cocktail shaker and shake until well combined.
• 4.
  Fill 2 serving glasses with extra crushed ice and strain in tequila mixture. Add pickled chilli, extra rosemary sprigs and some grapefruit zest from syrup to serve. Repeat for remaining cocktails.