Finely chop the onion and cut the provola cheese into small cubes.

Heat the olive oil in the frying pan over medium heat and sauté the onion until softened.

Add the ground beef and salt, then cook until the beef is browned and no pink meat remains.

Bring a large pot of salted water to a boil and cook the conchiglioni until tender.

Drain the conchiglioni and let them cool until they can be handled.

Combine 900 g tomato passata with the cooked ground beef in the mixing bowl and stir well.

Fold the provola cheese and béchamel sauce into the meat mixture until evenly distributed.

Grease the baking dish with olive oil and spread 250 g tomato passata across its base.

Fill each cooled conchiglioni with the meat and cheese mixture and place it in the baking dish.

Spoon the remaining tomato passata over the stuffed pasta and sprinkle with grated Parmesan cheese.

Bake at 200°C / 390°F for 20 min until hot and the cheese is melted.

Rest the pasta bake for 5 min and serve warm.