Clean and wash the Brussels sprouts and cook in boiling salted water for about 15 minutes. Peel and finely dice the onion. Heat the oil in a pan. Fry the noodles for about 5 minutes. Pour the Brussels sprouts onto a sieve and drain.
Add onion and Brussels sprouts to the noodles and fry for another 2 minutes. Pour in broth and bring to the boil. Season to taste with salt, pepper and nutmeg. Cut cheese into cubes and spread over Brussels sprouts and noodles.
Cover and fry for 2-3 minutes until the cheese has melted. Coarsely chop the hazelnuts and sprinkle them over the brussels sprouts and potato pan.