[rumbustion flip]

1 1/2 oz St. Ambroise Oatmeal Stout
1 oz Old Monk Rum
1/2 oz Allspice Dram
1/2 oz Demerara Simple Syrup
1 Egg

Shake once without and once with ice and strain into a rocks glass. Garnish the foam with Fee's Whiskey Barrel Bitters.
On Sunday night, Andrea and I went to Drink in Boston. For one of my cocktails that night, I asked bartender Misty Kalkofen for something with rum, and after a moments thought, she asked if egg was okay. With my affirmation, she set to work improvising a flip. I was pleased when I saw her reaching for a bottle of oatmeal stout to add to the mixing tin. Wayne Curtis in And a Bottle of Rum goes into great detail about the origins of flips using rum, beer, molasses, and a red-hot loggerhead and how things later evolved into the egg-laden drink we know today. Perusing the web, PDT in NYC has a similar recipe to the one Curtis described (minus the heated iron) and to Misty's but with a lot less spice notes:

Black Flip
• 1 oz Cruzan Blackstrap Rum
• 3 oz Brooklyn Chocolate Stout
• 1 Egg
Shake with ice and strain. Recipe did not specify glass or garnish, so a cocktail or rocks would work, and feel free to garnish with freshly grated nutmeg.

Misty's concoction added the spice notes from the Allspice Dram, the vanilla in the Old Monk rum, and the aged bitters with a loss of the blackstrap molasses notes. The bitters added more to the drink's nose for it donated a glorious cinnamon smell which did bleed into the first few sips. The drink proved to be rather rich from the rum, stout, and egg, and the demerara sugar helped to cut the dryness of the oatmeal stout. Moreover, the allspice from the dram appeared at the end and gave the drink a rather flavorful swallow.