Chop onion, put in a preheated sautee pan and fry until golden, add ground meat and stew until ready. Add a little water, season with salt, pepper and nutmeg and stew until soft but juicy.
Boil cannelloni in much salted water al dente. Drain the water and cut the tubes into 2-3 parts.
Fill the tubes with the prepared stuffing and put them vertically in a baking pan.
Mix cream with grated cheese (reserve some cheese for topping), pour the mix amongst macaroni tubes. Bake in an oven for 20 minutes at 400F (200C), covered with foil. Remove the foil, sprinkle the macaroni with the reserved grated cheese and bake for 15 minutes.
Garnish the ready tubes with greens.