Clean and wash the spinach. Cook them for 2 minutes in salty boiling water. Drain them and run some cold water on them to cool it down quickly (this will help them retain a nice green colour). Keep them in the colander for 1 hour to lose the excess water.

Then squeeze them with your hands to get rid of as much liquid as possible. Now cut them finely with a knife. Put the ricotta in a bowl, add the minced spinach, egg, 1½ cups (85 gms/3 oz) of grated Parmigiano Reggiano, nutmeg, salt and pepper and mix until well combined. Refrigerate until ready to use.

Put a large pot with salty water on the fire and bring to a boil. Cook the pasta sheets in it for 1 minute. Do this in batches (I use a shallow but large pot and I cook them in 1 layer, so I am sure they do not stick together). Remove them with a slotted spoon and put them on a clean tea towel to cool down.

Now take one sheet of cooked pasta and put 1/8 of the filling along the long side of the rectangle. Roll it over to make a cannellone. Do so for the remaining rectangles of pasta.

Take a big enough oven dish to fit all your cannelloni tightly. Spray it with some cooking oil (or melted butter) and pour some béchamel sauce on the bottom. Spread it well, especially in the corners. Put the cannelloni in the oven dish on 1 layer.

Cover the cannelloni with the remaining béchamel sauce and sprinkle with the remaining ½ cup (35 gm/1 oz) of Parmigiano Reggiano.

Bake them in a pre-heated moderate oven 350°F/180°C/gas mark 4 for 20 minutes, then broil (grill) them at 400°F/200°C for another 5 minutes.

Serve immediately.