This warming dish is inspired by Japanese ochazuke, a comforting bowl of rice with green tea poured on top. Traditionally, the meal may also be finished with grilled fish, sashimi or other toppings, but there is room for variation: You could swap out the hot tea for dashi, broth or other liquids. In this approach, the salmon is slow-roasted — which helps render some of the fat and keeps the fish meltingly tender — while a light shiitake mushroom and leek broth simmers. Divide cooked rice…