Zwiebelkuchen is an onion tart that originated in Germany. It is an integral part of the fall tradition in the Black Forest area of the country. In addition to onions, the tart has a dough, and contains ham and sour cream. Texturally, the filling is similar to that of a quiche.
In German, the word zwiebel translates as onion, and kuchen as cake or tart. A tart can contain as much as three pounds (about 1.4 kilograms) of onions. In its finished form, the onion tart shares features with both pizzas and quiches.
Basically, the tart base is a dough of white flour that gains bulk through a yeast addition. Also present in the dough are salt, sugar and milk. Butter and eggs, either separately or together,are also featured in recipes for the dough that forms the base and the sides of the zwiebelkuchen. It is the filling that contains the zwiebeln, or onions. Suitable onions can be either white onions or red onions, which must first be softened in butter.
In addition to onions, the filling typically contains meat, usually ham or bacon. The meat is cooked before the tart goes into the oven, sometimes with the onions. Eggs and sour cream also go into the filling, to give the tart its quiche-like texture. Optional flavorings include nutmeg, marjoram or pepper. Often, the tart has no dough covering, and has the filling open, but sometimes it has decorative top layers such as lattice designs from interlinked dough strips.
Zwiebelkuchen are associated with the Black Forest region of Germany. The traditional time of year for inhabitants of the region to make the tart is at the beginning of fall, after the summer glut of onions. Rather than a dinner dish, the tart is a lunch specialty.
One option is to eat the tart by itself, but other foods are also associated with the tart. Before eating the zwiebelkuchen, some Germans partake of some beef broth, called rindesuppe. A traditional accompaniment to the zwiebelkuchen itself, is a glass of new, young wine, known as Neuer Wein in the country.
Variations to the traditional zwiebelkuchen include a vegetarian option. This version simply omits the ham or bacon. Cooks can also use pork sausage meat instead of ham or bacon. Sliced mushrooms or cabbage can also suit the tart. Fat from the bacon can cook these ingredients down, and the cabbage can also undergo steam cooking before going into the filling.