Made a double of the recipe: 2 cubes sugar, 6 drops bitters, a large single shot of Panther's West Coast Espresso (little over 1oz) and 4oz Basil Hayden's with a king ice cube. Did not squeeze lemon juice in (I do into my "normal" old-fashioneds) but added the twist. Espresso seemed to overpower the drink a bit. The bitter of the espresso was the first, second and third taste sensation, with the bourbon only present in a hint of the aftertaste. As BH bourbon is normally quite smooth, perhaps a bolder tasting one (such as high-proof Booker's, maybe?) would help set off the flavors better. As it is, not horrible, but I'll stick to my normal old-fashioned and try out a different drink for the espresso cocktails.