These thick Japanese noodles are made from white wheat flour, salt, and water, and are usually served in a soup or with a dipping sauce. Udon are available both fresh and dried; dried udon are flatter than their fresh counterpart and closer in texture to linguine. Fresh udon noodles are fat and bouncy in texture, and tend to be more delicate than dried.
Cook both fresh and dried udon in well-salted boiling water until just tender (about 3 minutes for fresh, 8 minutes for dried). Drain the noodles and rinse them briefly under cold water before using in soup or another dish; this stops the cooking and also removes some of the surface starch, preventing them from sticking together.
Keep fresh udon refrigerated and use by their expiration date. Dried udon will keep nearly indefinitely on the pantry shelf.