Unadon is a Japanese dish consisting of grilled unagi (eel) fillets placed on top of steamed rice. The eel is grilled kabayaki-style, where the fish is split, gutted, butterflied, cut into squares, skewered, then diped in tare sauce before being grilled.
The tare sauce consists of soy sauce, mirin, sugar, and sake. It provides the necessary caramelization to the fish during the grilling process. Before serving, unadon is typically garnished with sanshō berries on top. In Kantō, the eel is traditionally steamed before grilling, resulting in a more tender texture of the fish, while in Kansai, the eel is simply grilled without prior steaming.