Add soy sauce, sake, mirin, white miso, garlic, sugar, and water to a bowl and whisk until ingredients are well incorporated.
Slice cabbage into wedges. Add wedges to an oiled and hot cast iron. Leave on its side for 5 mins or until charred. Flip to the other side and repeat.
Cube salmon and add to oiled cast iron. Cook for 2 minutes, flip and cook for 1 minute and repeat. Add miso sauce to cast iron. Cook until sauce is reduces into a glaze.
Serve in bowls layered with steamed rice, charred cabbage, miso glazed salmon. Garnish with toasted sesame seeds.