Gyudon is a popular Japanese dish consisting of thinly sliced beef cooked in a sweet and savory sauce, served over a bowl of steamed rice. The beef is simmered with onions and flavored with soy sauce, mirin, and dashi broth, creating a rich and flavorful topping for the rice. Gyudon is a comforting and satisfying meal that is quick and easy to prepare, making it a favorite choice for busy weeknight dinners.