Classic Irish Coffee is a strong, black coffee with whipped cream and a bit of brown sugar. Some Irish coffees use heavy cream but I chose FA Whipped Cream because it doesn't get in the way of other flavors.
VSO Espresso and Brazilian Coffee (SC) (WF) work well for me. YMMV however Irish Coffee is built upon black coffee. If you must substitute with a creamed coffee, take into consideration how that plays with the whipped cream.
I stepped out of tradition by adding VTA Coffee Liqueur. It adds some sweetness, coffee and booze without boosting the whisky. Of course, feel free to add more whisky. It won't hurt the mix and fades quickly. Enjoy!
If a boozy effect is important to you this works off the shake.