Look up Quarkkeulchen on the internet and you'll read that they're small pancakes from Saxony, made with potatoes, quark (a soft cheese product a bit like fromage frais), eggs, flour and sugar, fried in a pan. That's all well and good...except somewhere along the way, the Berliners decided the world of Quarkkeulchen was round. It doesn't seem like the rest of the world's worked that out yet, though, so let's take a look at the things and help spread the word...
What gets sold in Berlin as Quarkkeulchen is something quite different to the Saxon pancakes. They still contain quark, but there's no potato in the dough and they're deep fried as balls. The result is more like a doughnut, though they're often flavoured with lemon zest and cinnamon, giving them quite a different flavour, plus of course the quark gives them a heavier texture.
The word 'keule' in the context of food is normally a leg (e.g. Lammkeule - leg of lamb), but the name of these has nothing to do with legs! It comes from the middle German word for a ball - 'Kaule' - which, if used in the diminutive form, becomes Käulchen (little ball), which sounds the same as Keulchen.
I bought these ones on a wander down Unter den Linden, from a stall at the Opernpalais Christmas market, but you'll see little stalls selling them at other times of year if you keep an eye out for them. These particular ones also had raisins in them and were really, really good. I'm sure the amount of lard they soak up when they're fried makes them the sort of thing doctors would attach a 'danger of death' warning to, but with the temperature continuing to plummet, a bag of warm Quarkkeulchen is a really great thing to munch on while you walk the icy streets!