Żurek is a tart, full-bodied soup. Its base is zakwas, a mixture of rye flour and water that ferments for a few days, sometimes with garlic and bay leaf. The zakwas is added to a meat or vegetable broth and thickens the soup. White sausage, bacon, potato, mushrooms, horseradish and marjoram are often included, and the bowl is finished with half a boiled egg and, if desired, sour cream.
At Easter, żurek is made with white sausage — a fresh pork sausage seasoned with marjoram and garlic — and eggs, and it opens the Sunday meal. Many people serve it inside a round loaf with the interior hollowed out. It is one of the central dishes on the Easter table. For centuries, the meatless version was a fasting food, served alongside herring.
Żurek has regional variations. In parts of the country it is called żur, and there are recipes using other grains, buttermilk or mashed potato; barszcz biały, a sour wheat soup, is a close relative. Outside Easter, żurek appears year-round on the menus of restaurants and milk bars.