Note that the recipe specifies bourbon whiskey; this is not an arbitrary designation. The lemon juice helps to tamp down the sweetness and bring the sour notes of the whiskey to the forefront, while the syrup blunts its harshness. Considering the complete and utter lack of subtlety in any of the base ingredients, the result is surprisingly complex.
The official recipe includes a dash of egg white in the ingredients, but there appears to be some debate as to whether or not it’s an optional inclusion; given that this is a blog dedicated to doing things for oneself rather than following tradition, the Bartender tried it and discovered that the only noticeable difference is cosmetic. Therefore, the Bartender recommends that the aspiring mixologist weigh the pleasing aesthetics of the white foam at the top against the (admittedly small) possibility of poisoning from the raw egg, and choose accordingly.
1 1/2 oz bourbon whiskey
1 oz lemon juice
1/2 oz simple syrup
Shake and strain over ice in a rocks glass. Garnish with two maraschino cherries, or a cherry and an orange slice.
Source: IBA Official Cocktail recipe