Wash and clean fresh spinach and cook them in a little boiling salted water. Drain the spinach, squeezing well to remove more cooking water as possible. When the spinach are lukewarm, chop finely and place in a bowl with the ricotta, eggs, 100 gr. grated Parmesan cheese, pepper and nutmeg. Mix well with a spoon to form a uniform compound and salt to taste. Prepare the white sauce: heat the milk with pepper and nutmeg, melt the butter in a saucepan over low heat and add the flour. Stir quickly spiral with a whisk to prevent lumps. When the flour is completely mixed, add the hot milk, salt and continue stirring until the sauce is thick. Prepare now the cannelloni: cook the lasagna sheets for 1-2 minutes in salted boiling water and put them to dry on a clean cloth. Put at the center of each sheet a couple of tablespoons of filling then roll it on itself to form cylinders. Halve each cylinder to form the cannelloni. Place them on a well-oiled baking pan with a couple of tablespoons of white sauce on the bottom. Then cover completely the cannelloni with other white sauce. Sprinkle with grated Parmesan cheese and bake at 200 degrees for 20-25 minutes, using the grill for the last 5 minutes to brown the surface of cannelloni. Bon Appetit!