Method

• 1.
  Whiz coconut milk and caster sugar in a food processor until sugar dissolves. Transfer to a jug and set aside.
• 2.
  Roughly chop 5 limes, then add to food processor and whiz until broken down.
• 3.
  Stir the lime puree into the coconut mixture. Strain through a sieve into a serving jug.
• 4.
  Add the soda water, lemon juice and rum, and stir to combine.

• 5.
  Chop three-quarters of the mint leaves. Place in a mortar with the chilli and lime zest, and pound until well combined. Stir through the demerara sugar and place on a plate.
• 6.
  Slice remaining 1 lime in half. Using 1 lime half, rub the rims of serving glasses, then dip rims in sugar mixture.
• 7.
  Slice the remaining lime half. Fill glasses with ice and pour over cocktail. Garnish drinks with lime slices and remaining mint.