In a large cocktail mixer, muddle lemon verbena and sugar until the sugar blends with the herb.
Put the egg whites (or aquafaba) in the mixing cup. Cover and shake heavily until it becomes frothy. It's very important you do this step before adding ice, as the ice will water down and affect the frothiness.
Add the remaining ingredients and ice. Shake well to combine. But, don't over-shake or you'll lose some of the froth.
Strain the Drink into a martini or low ball glass. Drop 3 to 5 drops of bitters on top. You can use a toothpick to make a design like hearts in the bitters if you want. You could also garnish with more lemon verbena and citrus slices. And, a sugared rim is a nice touch.