I really don’t see any reason why not, as long as it’s a “strong” tasting brew.
And, not having any access to real Irish whipped cream, I use Redi-whip in a can. It may be sacriligeous, but at least it’s quick.
I just want to clarify what I said earlier about not using whipped cream. Of course there’s nothing wrong with enjoying whipped cream (or ice cream, as also mentioned) atop your fortified coffee. It’s just not quite an “Irish coffee” as I understand it.
There is a specific effect created by having a layer of liquid cream atop the coffee. One sips at the coffee at the edge of this layer, with glass tilted, and gets a little swirl of the cream entering the mouth with the cofee, but not yet combined. The flavor and mouthfeel that result are different from either a blended coffee drink or anything with sprayed toppings (which don’t move the way liquid cream does, not to mention the nastiness of corn syrup).
It is sublime.
Real whipped cream, from superb quality cream (look for that non-UHT), can produce almost the same effect, because it “falls back” to liquid in a much more natural way than the other things that pass for whipped cream.
You are, of course, totally right. My Irish Coffee can never equal what I had at Shannon, but hey, it’s tasty enough.
As mentioned above, there’s a sign on the wall at Shannon Airport claiming it was invented there to warm the first 20th century commercial transatlantic pilots, who had to hop into Ireland before heading on to other parts of Europe.
Yeah, here’s the whole story: http://www.irelandwhiskeytrail.com/irish_coffee_history_and_recipes.php
And here’s the sign in question: http://img.photobucket.com/albums/v400/murasakimegami/IrishCoffee2.jpg
My favorite Irish coffee:
Cup #1:
Strong cup of coffee
2tsp. sugar
1 shot good Irish whiskey
1/2 shot Irish cream
1 heaping scoop whipped cream
Maraschino cherry
Pour coffee, stir in sugar until dissolved; add whiskey and Irish cream; top with whipped cream and cherry.
Cup #2:
Strong cup of coffee
2tsp sugar
1 shot good Irish whiskey
1/2 shot Irish
As much whipped cream as you feel like
Pour coffee, stir in sugar until dissolved; add whiskey and Irish cream; top with whipped cream.
Cup #3:
Strong cup of coffee
A bunch of sugar
Whatever whiskey you have hanging around
A tipple of Irish cream
Pour coffee, stir in sugar; add whiskey and Irish cream.
Cup #4:
Strong cup of coffee
Whatever whiskey you have hanging around.
Pour coffee, set it aside. Drink whiskey straight. By now, who gives a fuck? 
Seriously, the best coffee drink I ever had that involved alcohol was in Colonial Williamsburg; to the table, they brought: a good mug of coffee, a tiny pitcher of Kahlua, a tiny pitcher of Bailey’s, and some vanilla ice cream. The waiter poured the Kahlua and Bailey’s into the coffee, then topped it with a tiny (melon-baller-size) scoop of vanilla ice cream. It was a combo of the perfect dessert and perfect after-dinner drink. Not Irish coffee, though, as whiskey was not involved.
“Coffee - Strong as a Friendly Hand”
Heh heh heh.
Well, “Irish cream” as in Bailey’s is just a combination of whiskey and cream, so you probably could think of it in terms of coffee, Kahlua, whiskey, cream, and ice cream. That meets my criteria, at least, of some type of “Irish coffee.”
Well, it was called “King’s Arms Coffee” after the name of the tavern. Whatever you call it, though, it was awfully tasty!