Like a margarita? Try this!
Put your coupe glass into the freezer.
Put the Gin, triple sec and lemon juice into a cocktail shaker with ice and shake until cold.
Strain the cocktail to remove the ice and put back into the cocktail shaker with the egg white.
Shake vigorously to emulsify the egg white and to create a foam.
Tip into your glass without straining.
Garnish with lemon peel.
Hints and Tips
The method we have given above involves a "reverse dry shake" method, which I found out about here. Technically you can get a froth by shaking all ingredients except the garnish without ice first for 30 seconds, then shake with ice. This is less fiddly as you don't have to strain back into the shaker, but be careful not to undo your hard work getting a good froth when you then add the ice!