Dear Hage9a, I love your term “blob” for the mixture that is added to the butter to make a frosting! (But then I studied physics, where “quark,” “strangeness,” and “charm” are all official terms.)
I’ve been trying to understand the different types of frostings and this is what I’ve come up with so far. Maybe some of you who have gone to chef school can correct my terminology:
Basic American-style “buttercream”—no “blob.” Powdered sugar is mixed directly with shortening (ugh), butter, or a butter/cream cheese mixture. A small amount of liquid is added as needed to thin it out. The large amount of sugar acts as the thickener for the icing. Tends to be very sweet and a bit gritty, because the sugar is not dissolved.
The cream cheese frosting from “The Sweeter Side of Amy’s Bread” is an interesting variation because the sugar has been dissolved in a little water and made into poured fondant before adding it to the cream cheese/butter mixture. This means it is not so gritty.
Rose’s white chocolate cream cheese frosting is another great variation of this theme, because the sugar is all part of the white chocolate and therefore not gritty. The cocoa butter in the white chocolate also provides thickening, since it is solid at room temperature.
All the other buttercreams use some sort of “blob”—a mixture which is beaten into the softened butter (or vice versa). The “blob” contains sugar, liquid (to dissolve the sugar), and some sort of thickener (eggs, starch, or both). It is generally heated to dissolve the sugar and activate the thickener.
Starch-paste or “roux” buttercreams: the “blob” is milk or water, sugar, plus a starch such as flour, cornstarch, etc.
Pastry cream buttercreams: the “blob” is milk (or other liquid), sugar, egg yolks, and starch.
Creme Anglaise buttercreams: similar to the above, but no starch.
Classic egg-yolk buttercream: again the ingredients are liquid (usually water), egg yolks, and sugar. The cooking method is different. The liquid and sugar make a hot syrup, which is then beaten into the egg yolks.
Italian meringue buttercream: the “blob” is Italian meringue, made with egg whites, sugar and hot sugar syrup.
Swiss meringue buttercream: the “blob” is Swiss meringue, made by heating egg whites and sugar and then beating to a foam.
Whole egg foam buttercream: the “blob” is made with whole eggs, mixed with sugar, heated, and beaten to a fine foam.
There can also be combinations of these. Rose’s “Silk Meringue Buttercream” uses both creme Anglaise and Italian meringue.
Well, that was fun, but I don’t know how much help it will be in solving your frosting problems. Do you have a thermometer? In my brief experience with buttercreams, I have found that they are quite sensitive to temperature. If they are too cold, the butter hardens and they curdle. If they are too hot, the butter begins to melt and they separate and curdle. I like to have two shallow pans standing by, one with cold water and one with hot water, so I can heat or cool the mixture as needed.
I recommend beating the butter until fluffy before adding it to the other ingredients—especially if you are using a hand-held power mixer, as I do. It makes for a lighter frosting and the butter incorporates more easily.
Patience is also important. I don’t know about the flour-paste type of buttercream, but the ones with Italian meringue can look really curdled during the time you are gradually beating in the butter. But if you keep the temperature in the right range, not too hot and not too cold, and keep beating, it all smooths out in the end. It’s like a miracle!