The one cocktail recipe you need to master before St. Patrick's Day? The Irish coffee. Fortunately, the American café where the American version of the cocktail was made, theBuena Vista Café in San Francisco, shows us how.

Legend has it that the drink was invented in 1942 in the western town of Foynes, Ireland, but the first one made in America was in 1952. Jack Koeppler, the then-owner of the Buena Vista Café, was determined to recreate the Irish coffee on his menu, even enlisting the help of a travel writer. The secret to the Irish coffee, they discovered? The cream that floats on top of the hot coffee, sugar cube, and Irish whiskey combination. It's a "lightly frothed heavy cream," not totally unlike the foamy head of a latte —but much thicker. Koeppler and his team of drinkers found that the cream had to be aged for 48 hours and whipped "to a precise consistency," according to the café's website. Of course, there are other ways to make it —you can do it with a sweet simple syrup instead of sugar cubes, and a whipped cream to make life easier.

John Concannon, of Concannon Irish Whiskey (a newer whiskey that hit shelves in January) went to the Buena Vista Café to show us the ropes of Irish coffee. Click here to see how to make an Irish coffee.