Clean, wash and roughly cut the savoy cabbage into strips. Peel and chop the onions. Heat the fat in a pot and fry half of the onion cubes in it. Add cabbage, braise briefly and season with salt, pepper and nutmeg.
Add 150 ml stock, bring to the boil, cover and stew for about 10 minutes. Clean and slice the mushrooms. Clean, wash and drain the chanterelles well. Cut smoked pork loin into strips.
Wash the thyme and marjoram, dab dry and chop the leaves, except for some marjoram for garnishing. Heat a little oil in a large pan, fry the slices of sausage briefly and remove.
Pour the remaining oil into the hot pan and sauté the remaining onions in it. Add mushrooms and chanterelles, fry lightly and season with pepper. Dust with flour and deglaze with 300 ml stock and cream.
Add marjoram and thyme, bring to the boil and simmer for 3-4 minutes. Stir in the smoked pork and let it boil for about 1 minute. Season the Kasseler mushroom ragout with pepper and possibly a little salt.
Spread the savoy cabbage vegetables on the bottom of a greased casserole dish and pour the cured pork ragout over them. Wash, peel and coarsely grate the potatoes. Mix cheese into the potatoes and season with salt, pepper and nutmeg.
Add the potato mixture as a topping to the ragout. Spread fat flakes on top as desired. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 40-45 minutes. Serve garnished with marjoram.