Note: To make Italian meringue you would usually make the syrup from water and sugar, in this recipe I have replaced the water with Guinness. This makes things a bit tricky since the Guinness sputters quite a lot in comparison to how the syrup would typically behave. Be sure to use a saucepan with high sides so that it will not bubble over.

Combine the Guinness and sugar in a saucepan. Heat until the sugar dissolves and the mixture boils. Keep boiling until the syrup reaches 243F (You can attach a candy thermometer to the side of the pot. I use an infrared thermometer and I’ve stopped at a reading of as little as 224F with perfect results – I must say though, that I’ve done this sufficient times now to be able to tell when the syrup is ready by sight – the bubbles pop more slowly than they do when the syrup first begins to boil).

While the syrup is cooking, in the bowl of a stand mixer fitted with the whisk attachment. Beat the egg whites till they form soft peaks.

With the machine still running, slowly pour in the syrup and continue beating until the meringue is cool and forms firm peaks. Add the salt.

Add the softened butter a bit by bit waiting till the previous addition is combined before continuing. (I like to switch over to the paddle attachment at this point simply because it’s easier to get the finished buttercream off the paddle than the whisk)

While mixing, the buttercream may appear to curdle but keep whipping and it will come back together into perfect beautiful buttercream, if it seems hopeless, place it briefly over some simmering water and whip it again.

Start pouring in the reduced Guinness. When you’ve poured about half in you’ll want to start tasting it as you may not want to add the full amount according to your preference.