So over the weekend I made 4 1/2 dozen cupcakes for a bridal shower. 1 1/2 dozen each of vanilla, lemon, and red velvet. I was so proud of myself for being hyper-organized. Normally I'm such a mess with these things and leave everything to the last minute and I'd wanted to avoid that this time.
I had all my dry ingredients pre-measured in ziploc bags (labelled according to recipe) the day before I was baking them so I wouldn't have to contend with a mess of flour. I made the icing a couple days ahead and put it in the fridge so that it was ready to go for decorating.
The cupcakes came out beautifully: all of equal shape and size (honestly ice cream scoops are the greatest way to fill cupcakes pans). And then I put the icing in my mixer to smooth it out and restore it to a spreadable consistency.
It's possible I should have let it come up to room temperature a bit more before throwing it on the mixer because the unthinkable happened. It broke. It broke and I found myself staring at a curdled soupy mess in my mixing bowl.
My first reaction was full blown panic. My second was an impulse to sit on the floor and cry. Because I had exactly and hour and a half to decorate the cupcakes before they were being picked up. (In my defense, this had more to do with my desire to maintain the integrity of the icing in my too-warm apartment than with my leaving things to the last minute.)
So I'm here to tell you how to save your buttercream if it breaks on you.
1. Set a pot of water on the stove to use as a double boiler. Put the broken buttercream in a metal bowl and set it on top of the simmering water. Keep some unbroken buttercream that you haven't tried re-whipping yet to add after.
2. Heat slowly, stirring constantly. Don't leave it over the water for more than a minute at a time. You'll be pulling it off and putting it back on repeatedly, but you don't want the butter to melt completely or it will never come back.
3. Once you have something that resembles creamy soup with minimal lumps, throw it back on the mixer with a whisk attachment (or use a hand mixer) and whip it on high. Just whip the hell out of it.
4. At first it will do nothing. DON'T PANIC! (or, you know, panic a little, but don't lose faith) Eventually it will start to come together and form peaks as it thickens. It's going to be looser than when you first made the icing.
5. Take some of the still-together, just-out-of-the-fridge buttercream you haven't tried to smooth out yet and add it slowly to your mixer. It should work in smoothly without breaking. Just don't add too much at once and make sure all the lumps are gone after each addition before adding more.
Voila! Ready-to-use, good-as-new buttercream! Aren't you glad you didn't panic?