In a frying pan, heat the olive oil and fry the chopped onion for a minute, add the finely chopped mushrooms, simmer everything until almost cooked, then add the finely chopped spinach (you can use frozen), simmer on medium high heat to excess fluid evaporated. Lightly season with salt and pepper, sprinkle with nutmeg. Optionally, you can add garlic and stew it with vegetables. Also, for convenience, spinach can be put out separately for 5 minutes and mix with onions and mushrooms.
The resulting stuffing (drain off all liquid!) Put in a bowl and mix with cheese and 1/4 Rikota part of grated parmesan. Stuff the cannelloni mixture gently.
Non-stick baking dish grease, put the tube close to each other. In a blender, combine the cream, milk and the remaining cheese mixture and pour the pasta. Bake 25-30 minutes at 180 ° C until golden brown.