Rinse the cod milt under running water. Boil water in a pot, blanch the cod milt briefly, then transfer to ice water. Pat dry with paper towels and cut into large bite-sized pieces.

Pat the cod fillet dry with paper towels and cut into bite-sized pieces.

Cut the tofu into bite-sized pieces. Chop the napa cabbage into manageable pieces. Slice the carrot into 5mm thick rounds. Remove the stems from the shiitake mushrooms and make a cross-cut on the caps. Slice the green onion diagonally into 1cm pieces.

Place the kombu and water in a pot and heat over low heat. Remove the kombu just before the water boils. Add the vegetables, tofu, cod milt, and cod fillet. Cover and simmer over medium heat until cooked through.