Juice of 2 limes
4 tsp sugar
1 lime, cut into slices
2 tbsp sea salt
2 tsp chilli powder (not too hot)
Ice and a cocktail shaker, strips of lime, to serve
Place lots of ice cubes in the cocktail shaker, pour over the tequila, Cointreau, lime juice, sugar, and shake well.
Put the salt and chilli into the Cole & Mason pestle and mortar, grind to a fine powder and tip onto a plate.
Wet the rims of 4 margarita glasses with a slice of lime and then dip the glasses into the chilli salt.
Place some ice into each margarita glass and strain the drink over the top, add a twist of lime peel to each glass.