Put the Brussels sprouts in plenty of boiling salted water and cook over medium heat for about 10 minutes. Coarsely chop the walnut kernels and roast them lightly in a pan without fat, let them cool down on a plate.
Put the sprouts in a large sieve, rinse with ice-cold water and drain again. Heat the oil in a large or two medium sized pans. Fry the gnocchi in it at medium heat for about 12 minutes, turning them over and over again.
Cut about half of the Brussels sprouts in the middle and pluck the outer leaves from some cabbage florets. Grate the cheese.
Fold the whole Brussels sprouts into the gnocchi and fry for about 5 minutes. Season with salt, pepper and nutmeg. Mix in 50 g cheese and 25 g nuts. Sprinkle the rest of the cheese and nuts on top.