Rocky Boston Sour is bewitching quite strong cocktail at 1.4 standard drinks. Shaken with 45ml bourbon and 30ml lemon juice with 15ml sugar syrup as well as 100ml ice and best with an entree or small snack. Just add half the ice to shaker then add all ingredients to shaker and vigorously shake. Pour all into glass and top glass with ice and garnish with lemon peel and served in a old fashioned glass cold.