Noppe is a type of Japanese soup or stew that is very popular in the Niigata prefecture, although many other areas of Japan have their own versions of the dish. The ingredients in noppe are intentionally flexible, because it is sometimes intended to be a way to use leftover vegetables and other foods. The basic stew is made up of vegetables such as carrots, bamboo shoots, taro and mushrooms that are quickly fried in sesame oil and then covered with water and allowed to boil until tender. The final soup is then thickened and served. During special occasions, especially the celebration of a new year, noppe is served as a traditional holiday dish.
The most common ingredients added when making noppe are carrots, scallions and fermented bean curd. A type of tuber known as taro also is usually added and is the primary vegetable found in the stew. Taro is a white, potato-like vegetable that is actually toxic until it is cooked to neutralize the harmful chemical. Other ingredients can include lotus root, ginkgo nuts, garlic and ginger. The skins of peeled vegetables or the stalks from herbs from other meals are sometimes added for flavor and to use what would otherwise be thrown away as waste.
Dried mushrooms also are usually added to noppe. They are first rehydrated in water and the dark, flavorful liquid that is left is added to the soup as part of the water base in which the ingredients stew. Additionally, the vegetables that are added can sometimes be first fried or seared in sesame oil. This adds flavor to the final soup and develops some of the sugars and textures of the ingredients.
Once all the ingredients are added to the cooking pot, it is filled with water until everything is covered. The stew is boiled, seasoning the water and concentrating the flavors. Many times, a special ingredient known as konjak is added to the liquid to thicken it. Konjak, also known as devil’s tongue, is a corm that is processed into a dehydrated form that can help to thicken the water in the same way that gelatin does.
Although noppe is known as a vegetable stew, meat is very often an ingredient. Specifically, chicken can be added, as can salted salmon. The water base can be replaced with anchovy stock and small, crispy anchovies can be sprinkled into the soup to add texture and saltiness. When the noppe is eaten as part of a holiday meal, it is customary to place a pile of fresh salmon roe in the center of the soup.