I was in Ireland recently to visit the Jameson Irish Whiskey distillery, and was surprised to find the Irish Coffee available at many bars in Dublin. Although the drink was created in Ireland at the Shannon Airport, it was made popular in America in the 1950s by a writer and a bar owner in San Francisco trying to recreate the recipe. I hadn't realized that the drink has returned triumphantly to its native home- and is made better than in most of the bars in which I've had it in the US. I ordered the drink three times in as many days.
The Irish Coffee is a simple drink: coffee, whiskey, sugar, and cream are the only ingredients. If you use a good coffee, raw sugar, and quality Irish whiskey you're almost there. The trick is in the cream.
It should float on the drink and is usually served nice and cold on top of the hot beverage. In Ireland the cream is wonderful, but there it is called "pouring cream." That is roughly equivalent to what is usually called "whipping cream" (not "whipped" cream in the spray can, either) in America but each country seems to have its own cream definitions.
The cream is liquid (but thicker than half-and-half) and is given a quick, light whipping before pouring it on top of the coffee drink. To prevent it from sinking, make sure you haven't just swirled the coffee (creating a whirlpool) and pour the cream over the back of a spoon just above the surface of the drink.
If you're making the drink for guests, you might want to let them know that one doesn't mix the cream into the drink but sips the coffee through it. You wouldn't want them to ruin all your hard work.
About .75 cups hot coffee
2 sugar cubes, preferably a raw or brown sugar
1.5 fl. oz. Irish whiskey, such as Jameson
Lightly whipped whipping cream or pouring cream
Prepare an Irish coffee glass or other heat-resistant glass by rinsing it with very hot water then discarding the water. Add sugar cubes to the bottom of the glass then pour in the coffee until the glass is about two-thirds full. Stir until the sugar is thoroughly dissolved. Add the Irish whiskey and more coffee, if needed, so that the glass is filled to half an inch or more from the top. Add the cream by pouring it gently over a spoon.