does anyone have any suggestions about making an italian meringue buttercream? I have a good recipe however every time I make it, it is a big soupy mess. I have a candy thermometer and heat my sugar syrup to 245deg then slowly pour into whippped egg whites. Sometimes I don't even get to the butter addition since I know it won't thicken up at that point. I'm not sure if the sugar mix isn't hot enough? It's come out correct once for me and I'd love to use it again but am running out of patience. Any help would be welcome!!

The recipe I have says to heat the sugar to 248-250 degrees. I wonder if a few degrees will make that big of a difference.

Hi
Cake Journal has a great tutorial on making IMBC. I just made it the other day without a candy thermometer, and it turned out great. HTH.
Kathy

Italian Meringue Butter cream: (It's best if you have a table top mixer, I don't so I get the mother to help)

5 large egg whites
100ml water
300g caster sugar
500g unsalted Butter
3-4 drops Vanilla Extract

Put the water and 250g of the sugar in a small saucepan. Stir while the mixture is heating, but stop once it starts bubbling. Boil the sugar until it reaches 121 degrees celsius (250 farenheit, or hard ball stage). Boil it on a rapid speed so the sugar doesn't discolour.
Meanwhile whisk the egg whites (Best to start whisking when sugar reaches 100 C/210F) and gradually add the remaining 50g of sugar. Whisk the egg whites until they get to stiff peak.
When the sugar reaches 121 degrees take it off the heat and pour it into the egg whites in a gradual stream (SLOWLY) between the side of the bowl and the whisk (try not to get it on the side of the bowl where it will set and the whisk where it could splash and could be dangerous). If the sugar gets too solid to pour, return it to the hob for a couple of minutes. Whisk for about 10 minutes (until the side of the bowl is lukewarm/cool).
Gradually whisk in the butter and vanilla extract. If it starts to look curdled don't worry you just need to keep whisking.

HTH

IMBC turning to soup is not unusual. Actually, it's kind of normal. I use Warren Brown's recipe from Cake Love and there is a YouTube video of him making it:

He has a lot of useful tips for making the buttercream. I add my butter to the meringue at room temperature. You need to let the meringue cool down before you add the butter, or else you will get a soupy mess. After I add the syrup to the egg whites I let it WHIP on high speed for 15 to 20 minutes. Feel the bowl to gauge how hot it is. After 15-20 minutes, add your butter, two tablespoons at a time. I do exactly what Warren Brown does.

Here are a couple of tips to make your buttercream work if it doesn't look like it should after mixing everything together:

Curdled appearance:

Butter was too cold when added. Take a kitchen towel, soak it in HOT water, and wrap the towel around the base of the bowl. When the little butter chunks have softened/melted to the point of looking incorporated, you can take off the towel and keep whipping.

Soupy mess:

Meringue was too hot when butter was added. This is kind of a difficult, high-tech fix-hopefully you can do it. Get a bag of frozen veggies out of your freezer, and rub it around the base of the bowl until the buttercream starts to firm up. Keep whipping!

At no point have I ever taken the bowl off the mixer and done anything else to it. Some people say to put it in the fridge, or put it over a bowl of hot water to get it to come together. I have never done that. I just use the above methods and keep whipping!

Meringue buttercreams are so forgiving. As long as you let your meringue cool for 15-20 minutes you shouldn't have too many problems after you add the butter. PLEASE watch Warren's video. It is so useful and I even took notes when I was watching it. My first try with this buttercream was perfect!