Cooked yolks in buttercream

I used the ATK version of buttercream: whip egg yolks in mixer, heat sugar and corn syrup until boiling, then pour the hot sugar mixture into the yolks with the mixer on low WITHOUT hitting either the side of the bowl or the whisk (how you are supposed to do this in practice, I have no idea). You whip that until the bowl is room-temp, then add the other ingredients (butter, salt, etc). Other recipes seem to call for the syrup to hit the side of the bowl. Neither method seems ideal, as when I did hit the bowl or whisk, it cooled and stuck to the bowl, but hitting the eggs seemed to have caused cooked eggs. I doubt there's any fix for it, but what's the right way to do this so I know for the future?



Poires A. June 23, 2013
You're describing a french buttercream, which does use egg yolks - it's rich but very delicious. I pour the hot syrup down the side of the bowl - a little will stick, but most should run in (that's the way I was taught at culinary school). The mixture should lightly cook the eggs, but not scramble or separate them - it whips up almost like a meringue. I'm not sure if I'm allowed to link here, but this is the post I wrote on my blog about making this buttercream, which has a video of my pouring technique -
Also, this is another way of doing it, which doesn't involve pouring syrup (Stella uses a Swiss-meringue-esque technique) =

Hope that helps.
Allison M. June 23, 2013
I'm not sure of the recipe that you are using because normally I use egg whites not the yolks. That being said, I heat the sugar and egg whites over a double boiler (mixer bowl over a pot of water) until they reach about 160 degrees F. Then whip in the stand mixer for about 10-15 minutes until cool, while whipping it gets nice and fluffy. Once cool, I add butter piece by piece and flavorings. The result is a super smooth & creamy, flavorful buttercream. My favorite is coffee flavored buttercream to use on chocolate cake.... Too yummy!

If your recipe calls for yolks, you could try doing it like I do for a swiss buttercream. I like not having to pour super heated molten lava into a moving mixer.
CecilyTechuan June 23, 2013

Sarah - That's what I was thinking, more like tempering the eggs for ice cream. These were not tempered at all, which I thought was strange but ATK is usually trust-worthy, so I went against my gut on it. I will definitely try this again and heat up the yolks first and maybe whisk in the syrup by hand before putting it on the mixer.

Allison - Yeah, I don't see how pouring the syrup into a moving mixer is a good idea...I'd rather do it by hand. I like swiss buttercream too, but it's less sweet and I'm making this for my kids' birthday party and they wanted the 'sweet icing' (which means my mom's shortening and powdered sugar recipe...can't go there!), so I thought that was a good compromise.

I ended up making a whole-egg buttercream where you cook the eggs and sugar together over a double boiler, and that seemed to go better.
Reiney June 23, 2013
Yeah, there's no fix for that. What temperature were your egg yolks when you whisked them? Try heating the yolks up, whisking (by hand) over a pot of simmering water until it reached sabayon stage first. Then swap to the stand mixer and pour in the hot sugar- it will help temper the yolks more gradually.

You're trying to hit the sweet spot where the yolks pool at the bottom of the whisk, not totally avoid the whisk itself. (You just don't want to pour the hot sugar over the top of the whisk.)
Recommended by Food52