Other common Czech soups are champignon or other mushroom soup, tomato soup, vegetable soup, onion soup (') and bread soup (served in a hollowed-out loaf of bread). ' is a traditional South Bohemian soup containing water, cream, spices, mushrooms, egg (often a quail's egg), dill and potatoes. It is typical in its thickness, white color and characteristic taste. The main ingredient is mushrooms, which gives it the dish's scent. "" is a regional specialty soup made from rye sourdough, mushrooms, caraway and fried onion.