Frederick the Great, who served as the king of Prussia from 1740-1786, enjoyed coffee brewed with champagne instead of water; with mustard instead of sugar.  Fortifying coffee has been a tradition for centuries.

If you’re at a wedding or special event where there is a barista and a bartender, you have the best of both worlds! It’s a rare barista who is licensed to serve alcohol, but he can most certainly prepare a single or double shot for a very classy cocktail or tasty libation.

As a party host, having a cocktail bar and espresso bar affords you two major benefits: it gives you the ability to offer your guests the latest craze in bar service, double-buzzed drinks featuring espresso; and it allows you to save on costs by ending alcohol service early while still offering specialty coffee drinks with their sobering powers. (A tip: for hosts considering fortifying coffee drinks, be sure to coordinate in advance with your wedding planner, barista and bartender.)
Here’s a simple recipe for an Espresso Martini. If you’d like to try this at home, remember, the quality of ingredients will impact the quality of the cocktail. Never use old espresso; freshly brewed only:

Espresso Martini
1 oz cold espresso
1 1/2 oz Absolut® vodka
1 1/2 oz Kahlua® coffee liqueur
1 oz white creme de cacao 
3 coffee beans
Pour ingredients into shaker filled with ice, shake vigorously, and strain into a chilled martini glass. It should be somewhat frothy. Instead of olives, garnish  with coffee beans.

If martinis aren’t your style, ask the bartender for a shot of rum, whiskey, brandy or cognac for your coffee, cappuccino or latte. If you’re in the mood for a more exotic flavoring, I recommend a variety of liqueurs:

Sambuca
Amaretto
Crème de cacao
Crème de Menthe
Calvados
Grappa
Kahlua
Tia Maria
Cointreau
Grand Marnier
Bailey’s Irish Cream
Frangelica