My go-to Italian Meringue Buttercream

Anytime I refer to buttercream on this blog, I usually start here. I thought I'd posted this recipe, but I can't find it, so I'll publish in a separate, bookmark-it-please post.

Buttercream is a very broad term used to describe all sorts of fillings/icings make with butter. Heck, sometimes people even call them buttercreams if they are made with Crisco. But, I don't do Crisco. Simple buttercreams (the kind you might find on a cake from a grocery store) are usually a mixture of butter/Crisco plus powdered sugar. They tend to be somewhat grainy, very sweet and hold up well to decorations. If they are part or all Crisco, they also stand up well to heat. (Butter melts, Crisco doesn't.)

More complex buttercreams involve cooking eggs (whites or yolks or both) with sugar to create a meringue, which is a very stable base for a buttercream icing. A meringue is basically a mixture of egg whites and sugar. For buttercreams, the meringue base (either Swiss or Italian style) is heated for safety and stability and later mixed with butter. The meringue produces an icing with a smoother, lighter texture, a less-sweet taste and a beautiful shine. There are two major differences between Italian Meringue and Swiss Meringue. In a Swiss Meringue, the egg whites and sugar are mixed together and the mixture is heated, usually over a double-boiler (indirect heat) to a temperature of 140 F (just almost too hot to touch and, significantly the temperature needed to kill salmonella). The mixture is then whipped until cool. This is a Swiss Meringue. To make an Italian Meringue, the egg whites are whipped separately while the sugar is heated with a little water to make a hot sugar syrup. This syrup is cooked to around 243 F (just at the end of the soft-ball stage) and then poured over whipping egg whites to form a very stable, glossy meringue. Once the meringue is cool, the butter can be added, along with any flavorings or additions. This is where it always starts!