Clean the Brussels sprouts (possibly carve the stem base crosswise), wash and drain in a sieve. In the meantime, season cream with salt, pepper and nutmeg. Peel and finely chop the onion. Heat the oil in a pot and fry the onion. Add Brussels sprouts and fry briefly. Deglaze with broth, bring to the boil, cover and cook for about 10 minutes.
In the meantime peel, wash and coarsely grate the potatoes. Fill the sprouts (with remaining stock) into a greased ovenproof dish. Spread the grated potatoes evenly over it. Add cream and bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for 40-45 minutes. Remove from the oven, sprinkle with nut flakes as desired and serve garnished with marjoram