I made this recipe for the first time. I really like the taste, but when I tried to frost the cake, it was full of air pockets. I mixed it on low speed using my KA until everything was integrated, then on 5 as directed.

Any ideas what might have happened?

I just made her BC for the first time this week and it was fine, in fact that's what I liked about it the most, the fact that there weren't any air bubbles in it. Did you use the paddle attachment and not the wisk? Otherwise, the only thing I can think of is it was whipped for too long or on too high a speed. I always mix all bc recipes on 2, even if it says to mix on a higher # I don't, it just incorporates more air into the icing.

You can use a rubber spatula to work the air bubbles out by back and forth motions not by stirring it. Just go from side to side sort of smashing the icing against the side of the bowl with the spatula.
HTH