Udon is both the name used for a specific type of Japanese noodle, and for dishes made with that noodle. Across Japan, these dishes are quite varied, from a plain quick snack to a complex dish with a wide assortment of ingredients. Many Asian markets carry udon, along with supplemental ingredients which can be used to make the dishes. It is also common to see a selection of udon choices on the menu of a Japanese restaurant, and in Japan, it is ubiquitous at small roadside stands and shops. People can also make udon at home, experimenting with an assortment of ingredients for their own unique takes on the classic dish.
The noodle is a thick wheat-based noodle which can be squared or round. As is the case with other noodles, udon will puff up when it is cooked, making the noodles even bigger, and very dense with a generally soft texture. The dried noodles can sometimes be found in coils, often with packets of seasoning or dressing to accompany the noodles once they are cooked. Dried noodles are also available in long sticks, like Italian pasta.
Traditionally, udon is served in a broth which may be supplemented with ingredients like fried eggs, chopped vegetables, fish cakes, dumplings, ham, or tempura fried shrimp. Each dish has its own distinctive name, such as kitsune udon, which is made with deep fried pieces of tofu, or yakiudon, stir fried udon in a dark sauce. Some restaurants accompany their udon menu with an assortment of illustrative photographs, for people not versed in the many options.
The most basic and traditional dish is kake udon, noodles made in a simple broth known as kakejiru. Kakejiru blends soy sauce, mirin, and dashi, three common ingredients in Japanese cuisine. Mirin is a type of rice wine, while dashi is a broth made from seaweed and dried fish, boiled together and then strained. Kake udon may be topped with slivers of green onion, horseradish, or carrot in some regions.
Different parts of Japan have different udon traditions, but as a general rule the noodles are served hot in the winter and cold in the summer. Cold udon in a refreshing broth can be a rather cooling afternoon snack, especially when paired with cool vegetables like cabbage and cucumber. In the winter, the broth tends to be heartier, with a heavier focus on protein and rich ingredients which will make the dish warming and filling.