Hokkaido-Style Salmon and Vegetable Packets (Chan Chan Yaki)

There are many different approaches to making chan chan yaki, a Japanese dish of salmon and vegetables flavored with miso and butter. The dish originates in Hokkaido, but we learned the version that inspired this recipe at Kermis, a stamp-sized restaurant in Tokyo. The chefs at Kermis enclosed salmon fillets, vegetables and a few seasonings, including miso, in foil, then baked the packets. Once out of the oven, the fish and veggies were dotted with butter and allowed to rest until a brothy, buttery sauce pooled in each packet.