Healthy Japanese Salmon Hotpot

Directions

Place one sheet of konbu in a large pot, and cover with 1L of water.
Bring to a boil, and as soon as it boils remove the konbu.
Add 50g miso, and 30ml each of sake, mirin, and soy sauce.
Stir until the miso dissolves, then arrange the following ingredients in a neat presentation:
3 leaves of napa or other cabbage, cut into 3cm squares, a handful of chrysanthemum greens or other greens, 2 shiitake mushrooms with a cross cut into their caps (see video for details), 50g of shimeji, enoki, or other mushrooms, 1 leek, sliced diagonally into 1cm pieces, and 125g of firm tofu sliced into 1cm pieces.
Cover and cook until the napa stem is tender, then add 500g of sliced salmon and a 20g pad of butter.
Cook until the butter melts, at which point the fish should be done.