Nothing is more luscious, more smooth, more light than a good Italian Meringue Buttercream Frosting! So many people struggle with making it, as they rush the process... relax, take your time, walk away and do something else while it cools....
Italian Meringue Buttercream Frosting
1 1/2 cups of white sugar
3/4 cup of water
1 teaspoon glucose
5 large egg whites, room temp
Pinch of cream of tartar (1/4 teaspoon)
450 grams of good quality unsalted butter, room temp and cut into 1cm cubes (and a little extra in case)
Flavouring of your choice - I usually use a good teaspoon of organic vanilla bean paste (Queens)
In a sauce pan, add water, glucose and sugar (in that order) and heat on a medium to high heat until the syrup reaches 118 to 120 degrees - I use a heat gun to check the temp regularly - purchased for like $15 on eBay, best investment!
Meanwhile, place eggs into your mixer and use the whisk attachments. Can I highly recommend your metal bowl... just in case... When the temp of the syrup approaches 110 degrees, start to whisk up your egg whites. When they are nice and frothy, throw in the cream of tartar.
When your syrup is at the right 118 to 120 temp, remove from the heat and start to "stream" slowly into the mixer while it's still going - be careful your speed isn't up too high to avoid splash back and not to low to the sugar isn't sinking straight to the bottom of the bowl. Keep streaming it in until it's all incorporate. Please be super careful, this sugar syrup is so hot it will give you 3rd degree burns if you get it on your skin, so be mindful when utilizing it. And keep children away, please do not allow children to do this step - this is an Adults Only Step!!
Set your mixer to a medium speed and let it go. Keep it running while the mixture starts to cool. By now, it's a gorgeous, silky meringue you usually associate with pavlova. Keep checking the temperature of the mix by using your temp heat gun, or touching the outside of the bowl. When it reaches below 30 degrees (or cool enough to grasp the bowl with both hands without feeling hot to the touch) start to add a few cubes of butter. Just a few... like 3 or 4.... and walk away for another minute.....do something else!!! Don't be tempted to rush this bit. This is where it all goes to soupie crappy mess as people add in too much butter while it's still too hot....
Add another few cubes. And walk away for another minute - then add a few more - touching the bowl you will find the temp has dropped right down, now you can stand there and add in a a cube every couple of seconds and watch them incorporate.
Once all the butter is gone, add in the flavouring of your choice. Mix for a few seconds. Now, you can switch off the mixer. This is your time to taste test for balance of flavour and firmness of the butter cream. If it doesn't quite hold it's shape, means it was still a little too hot when you added the butter. I noted a bit of extra butter at the top, let the mixture sit for 10 minutes to 20 minutes to cool a bit longer and add in another 50 grams a cubed butter while the mixer is going to firm it up a bit more.
Notes: If you ended up with a soupie disaster, stop adding the butter, keep the mixer on a low speed and leave it to mix slowly for 10 to 15 mins, then try adding in a few more bits of butter - this usually can rescue it if you haven't already added all the butter. If you have soupie disaster at the end, you are screwed! Naughty baker and didn't listen to my advice above about taking it slow!! Now, place the bowl in the fridge for 10 minutes - and try to mix it again - "If" it's salvagable, this will do it. Colours - gel colours are best. I use Americolor brand. This is an egg based butter cream, so be mindful of longevity.