Boil the Brussels sprouts in salted water until they are al dente, drain.
Halve the onion and cut into thin slices. Heat the butter in a pan and fry the onion until translucent. Deglaze with cream and add the processed cheese. When the cheese has melted, stir in the salt, pepper, nutmeg and curry into the sauce. Bring to the boil briefly, add the Brussels sprouts, serve hot.