For the tomato sauceHeat the oil in a large pan; dice the onion, squash the garlic and heat them in the pan with the oil. Let cook gently for about 2 minutes, making sure not to overheat the garlic. Then, put in the tomatoes chopped with the salt and the sugar and let the sauce gently simmer for 20 minutes low heat, until has thickened, add salti f needed, some dry oregano and set aside.
For the béchamel:
Melt the butter in a saucepan at low heat then add the flour. Stir well until a past forms (the “roux”), continue cookign for 1-2 minutes, stirring, then add the milk to the paste and the salt. Let cook for about 10-15 minutes, always stirring , until the sauce has thickened. Set aside.
For the cannelloni:
Fill a pot with 1,5 liters of water, without any salt, then bring it boil. Add the peas and boil them for about 5 minutes. Drain the peas and set aside.
Put the oil in a pan with 1 clove of garlic, crashed, the onion chopped and let cook for 2 minutes, then add the peas, season with salt and some leaf of rosmarino and make cook for about 5 minutes (you don’t need to boil the peas if you use canned peas). Set aside.
In a large bowl put the ricotta, stir it to make it creamy and add the peas. Add some origano, 30 gr of parmesan, season with salt and set aside.
Take the cannelloni tubes and, with a teaspoon or a piping bag, put the mixture into them, and lay them in an oven dish.
Put some tablespoon of tomato sauce in the bottom of the dish, then lay the cannelloni.
Spread the tomato sauce over the cannelloni, then, with a tablespoon, spread the béchamel sauce and 2 tablespoon of parmesan and some flaky butter. Place in the oven at 180°C (350°C) until the cannelloni are tender and the top is golden, about 30-35 minutes.
Remove from the oven and let stand for a few minutes before serving.