Boil the sfoglia and let it cool on a cotton cloth. In the meanwhile, prepare the stuffing for the cannelloni. Whisk the ricotta with the parmesan and the provolone in a bowl, add the chopped chive, the lemon peel, salt and pepper. Take the sfoglia and cut it in two parts, place the stuffing on the three-quarters and roll. Keep the cannelloni in the fridge for 30 minutes. Prepare the béchamel by melting the butter in a little pot (it is very important to keep the fire at the minimum), then add the milk. At this point add the combed flour while stiring with a whip. Now add a pinch of nutmeg, salt, parmesan cheese and grated truffle. Keep stirring while the béchamel gets dense. Take it out of the fire when it gets the consistence you prefer. Paint the baking tin with butter and pour a couple of spoons of béchamel; then place the cannelloni. Cover them with plenty of béchamel and cook in the oven at 180 C° (350 °F) for 30 minutes. Once they are cooked, let them rest in the oven (turned off) for other 20 minutes and serve.