German buttercream frosting is one of the four and a half main kinds of buttercream frostings, and one that’s not as common here in the US as it really ought to be, because it’s both really easy and you can pack it full of flavor.
The recipe is simple:
- 1 pound room temperature (~65F/19C) butter
- 1 batch of pastry cream
Beat the butter until it’s light and fluffy. Beat it a lot. Once it’s fluffy start adding in the pastry cream one spoonful or so at a time, beating to incorporate. When all the pastry cream is added and the frosting is fully beaten (it’ll be a normal buttercream frosting consistency, fluffy and reasonably spreadable) then you’re done.
If your butter is too cold the frosting will be a bit thick and hard to work with, and if it’s too warm it’ll be thin and a little loose. Like with all other buttercreams, or most anything else that uses butter, temperature is important. If you’re somewhere warm, add extra corn starch to the pastry cream (it can handle up to about twice what my linked recipe has) which will make the pastry cream nearly solid but lightens up with the butter and helps offset higher temperatures.
This is enough to frost an 8″ or 9″ round cake. It might be a bit tight with a 9″ if you frost the middle, too, but seriously don’t do that — the middle layer should be something else that complements the cake and buttercream. (In mine here it’s lemon curd)
Why German Buttercream’s great
German buttercream frosting is great because it’s so simple, doesn’t require molten sugar, and you can make up the pastry cream ahead of time. If I want an actual white frosting I’d use something else (probably a Swiss buttercream made with goat butter) but for anything else? This is my current go-to frosting.
The other thing you have going for you here is that you can pack a huge amount of flavor into the frosting. Most buttercream frostings are buttery and sweet, but only mildly flavored. Some people like that but I prefer something with a bit more presence in the cake, and that’s what you have here. In the pic the (somewhat amateurish) cake is frosted with a buttercream that’s about 1/3 lemon juice by weight. It’s intensely lemon, and even though I added a bunch of sugar (almost 200g of powered sugar) it’s still really sour and it’s just awesome.
It’s really hard to get anything even close to that intense a flavor from other kinds of buttercreams. In some cases, where your flavoring agent is dry and intensely flavored like with freeze-dried berries, you can manage but it’s hard and you’re limited in the flavors available to you. For a German Buttercream, as long as your intense flavor is liquid you can go wild with it.
An apple spice cake with apple-cider frosting? Just make your pastry cream with cider and that’d be awesome and now I want it. Cranberry frosting for a chocolate-cranberry cake? (Or, at least, a chocolate cake with a cranberry chutney filling and cranberry-juice-based frosting) Nice.
Once the office re-opens I fully intend on making a rich chocolate cake and a Jameson’s frosting. (Which, if I math out right, will be about 10% ABV (maybe a little less, there’s air in that volume), so eat responsibly when it happens)