In its way, żurek—pronounced “zhurek”—is the most humble of all Polish soups, and at the same time the most exotic, at least to the foreign palate. It has traditionally been eaten at Easter, but now is found on menus all year-round. Though distantly related to the bread and garlic soups of Spain and Italy, its base is not meat or vegetable broth, but zakwas. Zakwas is made from rye bread and water and is, in turn, distantly related both to sourdough and to Russian kvass (a fermented drink). In Poland, zakwas is available in bottles at ordinary supermarkets. Outside of Poland, you can find it in specialty ethnic markets, and even online. If you do have to make it yourself, although it sounds odd and intimidating, it is in fact extremely easy. But it does require planning a few days in advance.