Procedure for the Béchamel: Bring the milk to the boil. In a separate pot, melt the butter over a gentle heat and add the flour. Once the milk is boiling, pour it over the butter mixture, stirring continuously to prevent lumps. Bring the béchamel to the boil, season with salt and pepper and set aside.
Cannelloni pre-cooking: Bring plenty of salted water to the boil, add the cannelloni and cook for 3 minutes. Drain and place on a flat surface, allowing them to cool. Keep the Cannelloni separated to prevent them from sticking. Do not rinse with cold water. Barilla Cannelloni can also be filled without pre-cooking. Just add a little more béchamel sauce and cook 10 minutes longer.
Procedure for the Filling: Peel and slice the shallot. Sauté in a pan with butter, then add the asparagus, cleaned and cut into rounds. Cook gently, until the asparagus are tender, but still green and bright. Blend in a mixer together with the ricotta cheese, the egg, breadcrumbs, tarragon, salt and pepper.
Assembly: Fill the Cannelloni with the filling, using a piping bag. In a large baking tray, place ½ of the béchamel sauce and spread evenly.
Place the cannelloni on top of it and then cover them with the remaining béchamel.
Bake in a preheated oven at 180°C for 20 minutes.
Allow to rest for 10 minutes before serving.