In Peru, there are almost as many ways to prepare potatoes as there are potato varieties. Since Neolithic times, Indians in the Andes have processed them into hard nuggets called chuño through a complicated process that involves freezing, defrosting, crushing, pressing, refreezing, and sun-drying in very cold air; the results are used as the basis for carapulcra and other stews and soups. Nondried potatoes are baked or boiled and served with sauces that might include tomatoes, onions, chiles, cumin, coriander, and cheese. More sophisticated preparations include causa, a hearty, elaborate dish of mashed potatoes and fish in the form of a cake. Stuffed potatoes are another delicacy; in the version made in the town of Arequipa, in southern Peru, they are filled with chopped meat—pigeon is typically used—mixed with onions, raisins, and olives, and then fried crisp. Simpler to make is the earthy ocopa—a boiled white potato served with a sauce of onions, peanuts, cheese, and chiles and a garnish of olives and hard-cooked eggs.