Goddamn, this is a good winter warmer cocktail. Here's what you will need to gather around your Boston Shaker:
2 ounces of bourbon. If at all possible, get your hands on a bottle of Infusion Diabolique, a bourbon infused with handfuls of stuff like figs, cinnamon, and cloves. It goes very well with this drink. This is likely not possible, since it's only sold in two stores, so go for a more neutral bourbon, like Woodford Reserve. I would caution against anything with a flavor profile outside the norm (for example, Michter's) or anything overly expensive (look, this is a mixed drink).
1/2 ounce of pimento dram. This is going to be the hardest ingredient to find, but this is a cold weather cocktail in my opinion, and I'm telling you about this now so you have ample time. The best dram you'll find is St. Elizabeth Allspice Dram, made by Haus Alpenz and imported into the U.S. by Rothman & Winter. It will cost you approximately $20 for 750 mL.
1/2 ounce of lime juice. My wife insists on fresh lime juice over the bottled stuff. I don't notice the difference so long as it hasn't been sitting in the bottle for too long.
a dash of Angostura bitters. There was an Angostura shortage a few years back. It is no longer an issue.
a dash of simple syrup. You can omit this if you want. I strongly suggest doing so. But it was in the original recipe, so there it is.
Throw all of this together, with ice, into the Boston Shaker. Shake vigorously. Pour it out into whatever glass suits you. I prefer a lowball glass. The resulting mixture will look not unlike apple cider - the brown color comes from the liquor and the translucency is provided by the juice. The acid in the lime is all that is left of it upon tasting, as a wonderfully warm and inviting taste hits the tongue; earthy hints of cloves and nutmeg and cinnamon swirl around in the mouth. It is not sharp or biting in the least, and the aftertaste calls out, saying “Put me in a flask and smuggle me into a playoff game.”