Winters in Japan mean congregating around heat. We camp out under kotatsu, Japanese heated tables, and share all kinds of nabemono, hot one-pot dishes such as shabu-shabu, oden, or sukiyaki. Combining a medley of ingredients in a simmering broth, these Japanese hot pots are cooked at the table, to be enjoyed as a communal feast. Sukiyaki, in particular, is seasonal party food—a staple on New Year’s tables, and all through the rest of winter. The dish is traditionally prepared in a wide cast-iron pan, which keeps the contents bubbling hot. It begins with a shallow layer of warishita sauce, a sweet and savory blend of soy sauce, sake, and sugar, thinned with a splash of kombu dashi, an umami-rich kelp broth. Into this fragrant, simmering base go paper-thin strips of richly marbled beef, followed by grilled tofu, noodles, mushrooms, and the best of winter’s vegetables: nutrient-rich shungiku (chrysanthemum greens) and …