Quark
A smooth, soft, slightly sour fresh cheese of Germany and Central Europe, set mainly by acid.
Also: Quarg, Topfen, twaróg, fresh curd cheese
Quark is the everyday fresh cheese of Germany, Austria (where it is called Topfen), Poland (twaróg) and much of northern and eastern Europe. Skimmed or whole milk is soured with lactic bacteria and a little rennet, then the soft curd is drained and often smoothed in a separator. It is moist, mild and gently tart, with a texture between thick yoghurt and ricotta. It is used everywhere: in German Käsekuchen, Austrian Topfenstrudel and Topfenknödel, Polish sernik and pierogi ruskie, and as a spread with herbs and linseed oil. It is close to Russian tvorog and French fromage frais, though tvorog is usually drier and more crumbly.