Today it comes in many shapes, including the usual flat, rectangular form, and can be adapted with many ingredients such as leeks and cottage cheese. It is commonly prepared at home but can be found in many German restaurants across the country. Zwiebelkuchen is commonly consumed during the annual grape harvest, and it is recommended to pair it with traditional young wines.
Although it translates to onion cake, German zwiebelkuchen is better described as a savory onion pie. The base of the dish is a thin, buttery crust that is usually made with yeasted dough. The center of the pie is filled with a combination of caramelized onions, smoky bacon, and a creamy mixture of eggs and sour cream.
The pie is usually spiced with salt, pepper, and caraway seeds, which give the dish a deep and earthy flavor. Even though there are several varieties of zwiebelkuchen, it is traditionally baked as a round deep-dish pie. In the past, this savory delicacy was made with sour milk and plain bread dough–common staples in many German households.