Step 1

Add all the ingredients except the soda water to a cocktail shaker with ice

Step 2

Shake well until the outside of the shaker becomes frosted

Step 3

Strain out and dry shake the cocktail again, this time without ice, to froth up the egg white

Step 4

Strain into a highball glass with a couple of ice cubes

Step 5

Top up with carbonated soda water

Step 6

Garnish with a lemon slice and serve