ADon't! I was just a little short of pasteurized egg whites so I thought I'd try and make up the difference with fresh - 3 eggs worth. Figured I would cook them anyway so let's try... My first smbc total failure! The meringue came together perfectly, the bowl was cool to the touch, but after adding the butter it just did not want to come together. I let it go on low for half an hour and it was barely coming together. I tried adding flavoring and it totally separated into a curdled mess. After beating and beating I decided to try a different strategy. I melted the entire thing until smooth and it's currently cooling in the fridge. I'm going to retry beating later. Sigh...
fwiw--i doubt it is the combination of egg whites--however after being melted, the water in the butter could separate out and this might be the end of it--melted butter is a much different substance than room temp butter--
curdling is normal--then let it chill if it does not come together by beating--then after it's chilled re-beat--
i'm not sure about the outcome after it getting melted--
one time mine curdled after it was made successfully--omg--what happened is the beater in my newer mixer does not touch the bottom and some of the whites never got fully whipped but still it came together after i beat the hell out of it even after all that--
hope yours works out! it's amazing stuff
but you could even try a little to a lot of powdered sugar for a last ditch effort (aka hail mary) if it comes to that--good luck!
I've mixed both, with no difference in result. Also the 11 wire whip super duper whips up SMBC. It came with my last 7 qt. KA. Makes SMBC in half the time.
I also add Powdered sugar to all of my SMBC, we all have a sweet tooth here. The icing is still silky smooth.
I have run out of real egg whites and supplemented with the pasteurized ones before and did not have these results.
If your eggs whipped up in a meringue nicely, then I suspect it was not your eggs. Sometimes, the bowl cools to the touch and there are still pockets of warm meringue in the middle that can melt room temperature butter. Because of this, I do not let my butter get to complete, soft, room temperature. I like it to be soft yet cool to the touch. If I am in a time crunch, I place my mixing bowl in an ice bath to bring the temp down.
Adding powdered sugar is a great idea. However, my first attempt to save it would be to add some melted white chocolate. The handful of times it has happened to me, this has been my go to fix and has always worked like a charm.
AThanks for all the replies. The bowl was cool to the touch, the butter was room temp, I went to the whisk and added powdered sugar - just. was. not. happening! Maybe the butter needed to be cooler and there were "hot pockets" somewhere in there. It still tastes great. I melted and then whipped it but it looks grainy. I refuse to throw it away. Plan B: melt it down again and use it for cake fondue! Shout out to all those crazy customers who call fondant "fondue". :D