Could not find the Bittermens Mole Bitters, and substituted Scrappy's Bitters Chocolate bitters - not the same flavor profile of the pepper in the Bittermens, but you have to do with what can be found. Tried it both with and without the bitters. Used Offley 10 year old Tawny Port. I liked it best without the bitters -- probably because the Port has a little hint of bitter in it, and the touch of spice from the rye in the Basil Hayden make the bitters too, too much for my preference. The result is a perfectly balanced cocktail where all the ingredients played well with each other to give a very nice and easy to drink autumn bourbon cocktail. It has more depth and complexity (probably from the port) and less sour (probably because the maple syrup in place of sugar or simple syrup) than a whiskey sour. The Basil Hayden is perfect for this cocktail with its caramel sweetness, perfect amount of proof (80), and hint of rye. I've tried this with other bourbons (Makers 46, Four Roses Single Barrel, Larceny and Jack Daniel's Single Barrel, Angel's Envy), and found they over-power the drink. So, make this with the Basil Hayden's, or it is not the cocktail it could be. This is a very, very nice autumn-winter bourbon cocktail if you like citrus in your bourbon drinks. Cheers!