To make the cocktail, add the strawberries, grapefruit, Stoli Crushed and sugar to a blender and blend until smooth. Keep this in the fridge until ready to serve. Add the sparkling water right before serving.

Fill glasses with ice cubes and then pour the drink over top.

To make the rim, add the sugar and salt to a small plate. Rim the glass with a wedge of grapefruit, then dip it onto the plate so that the salty sugar sticks to the rim.