And for those who follow me, you know I'm an irreverent baker, at best. In retrospect, that would have been a great name for this blog: The Irreverent Baker. And now that I've said that out loud, someone's going to go and steal it. Or else it's already been used. Man! I sound paranoid tonight.
Anyway, this is one of my most popular frostings. It started out as a base recipe from Alton Brown, because he's my go-to guy, but I've definitely changed it up to suit the Irish cream.
First things first: if you're using a stand mixer, use the paddle attachment. If you're using a hand mixer, that's cool. You'll build some definition in your shoulder muscle.
And there is a difference between butters, folks. The "Eurpopean" style butters are not only going to be more expensive, but they will also yield a smoother, creamier mouth-feel. Regular old butter does fine as well, and sometimes I prefer it. Honestly, I usually mix the two. Experiment with them both and decide for yourself!
Also, I know some people get nervous when introducing raw eggs into uncooked food. I get it. The truth is that salmonella is carried on the outside of the shell, so if you crack the egg on a flat surface (a counter or plate, NOT the edge of the bowl), your odds of contamination are low. Other options are whole powdered eggs (usually found near the baking soda/cocoa powder/meringue powder in the baking aisle), but these don't work as well as a real egg. Some grocery stores--more and more of them, it seems--sell pasteurized in-shell eggs. These are my favorite. I buy a dozen and keep them aside just for frosting. But honestly… I have literally, in the truest sense of the word, made variations of this frosting hundreds of times with raw, unpasteurized eggs, and I have never once had anyone get sick. Your call. And no, something like egg beaters or egg whites pasteurized in the carton won't have the same effect, because the yoke and the emulsifying factor is what gives it the smooth texture.
Also, I love me some Bailey's Irish Cream. Mmmm-hmm. But that stuff is crazy expensive, amiright? My favorite substitute, which manages to pack all the flavor for half the price, is Merry's Irish Cream. It's good stuff. Carolan's is a distant third, and Ryan's isn't even on my list. And no, no one pays me. It's just that I prefer to use the cheaper stuff for frosting and the more expensive stuff for drinking, though Merry's is so good I use it for both.
Okay, with food safety lessons and liquor recommendations aside, let's get down to business:
6 oz of butter unsalted butter, room temperature (1.5 sticks)
3 oz of shortening (if you eyeball it, the volume is close to a stick of butter)
1 egg, room temperature
1 lb of powdered sugar (four-ish cups)
dash of salt (1/2 tsp or so)
tsp vanilla (optional)
Irish cream (few tablespoons to 2/3 C, to taste)
Mix the butter and shortening together in the bowl of a stand mixer with the paddle attachment (or with a hand mixer) until combined. Up the speed and whip the heck out of that fatty goodness until it's creamy and light yellow, 2-3 minutes. Scrape the sides, add the egg, mix to combine, and then up the speed again until smooth, glossy, and picture-perfect, another 2-3 minutes. Add the powdered sugar slowly in 3-4 installments, mixing on low speed until combined. Then up the speed to medium high and walk away and do the dishes or check Facebook for 4-ish minutes. Or, if you're using a hand mixer, just think, "my shoulders will look fantastic, my shoulders will look fantastic, my shoulders will look fantastic."
When it's light and fluffy, add a dash of salt and vanilla (the vanilla is optional. The salt is highly recommended). While the mixer is going on low, add Irish cream a little at a time. Don't be shy, but don't be crazy. Chances are, you're going to add MUCH more than you think is safe. Honestly, I start with about 1/4 cup, and then add from there. I can't tell you the exact amount, because everyone's taste is different. I can tell you that I generally add as much Irish cream as the frosting can handle while still holding a peak when I lift the beater out. It's a fine line. Too much, and the frosting will start to separate.
When you have it to your desired flavor/consistency, fill a piping bag or slather a spatula and frost to your heart's content.
The frosting will be shelf-stable, so if your cake is going to be eaten within 24 hours, it can stay on the counter. If it will be eaten later, or it's really hot outside (hard to think about in December), refrigeration is recommended--especially if your egg is unpasteurized.