Bulletproof Rum Espresso Martini

It’s no passing coincidence that the meteoric revival of the espresso martini and the growing sophistication of coffee culture are happening simultaneously. There’s an exciting dialogue between the two trends, where the highly adaptable template of the classic Espresso Martini is serving as the sandbox in which cocktail and coffee nerds alike can play.

The standard espresso martini build usually includes vodka, coffee liqueur, espresso, and simple syrup. Riffs on the drink tend to swap the base spirit, experiment with the growing roster of coffee liqueurs, use different coffee varieties, or all the above. This recipe exploits a hack that both bartenders and baristas would recognize: using fat to make a drink more velvety.

Bulletproof coffee, a relative newcomer to the coffee drinker’s repertoire, uses butter to enhance the richness of your humble joe (supplements, usually MCT oil, are also sometimes added as a part of this wellness trend). Fat-washing is a popular method to make spirits more viscous and impart savory flavors; all it means is that the spirits are mixed with some source of fat—whether that’s bacon fat, sesame oil, coconut oil, or melted butter—and left to infuse in a freezer, where the fat will separate out and can be easily removed.

This Bulletproof Rum Espresso Martini has a base of dark rum that’s fat-washed with vanilla-tinged brown butter. Rum and coffee are already longtime friends (see Kahlúa). The fat-washing process gives the drink an extra-velvety texture and amplifies the tropical notes that are tucked away in coffee.

You can make this coffee cocktail with 1 oz. unsweetened cold brew concentrate, such as Grady’s, but the flavor will be less robust than if you use freshly brewed espresso. If you don’t have access to an espresso machine or stovetop moka pot, Cometeer’s frozen coffee capsules, thawed, make a great substitute.