Rub the rim of the glass with the lemon and dip it on a plate with salt. Place 2 ice cubes in another glass and pour two ounces of CONVITE, a little lemon juice and a pinch of salt, and finally the grapefruit soda. Stir vigorously. Pour the cocktail into a glass and voilá!

You can also use a grapefruit to rub the rim of the glass.