Clean and chop onion, carrot and celery.
Heat the oil in a large pan, add the chopped vegetables. After two minutes add the meat. Cook for 10 minutes over medium heat. Add the tomato sauce, cover the pan and let simmer for 1 hour. Add the béchamel and parmesan.
Grease a baking pan with butter, compose a layer of sheets, and then cover with the prepared mix. Cover the mix with the lasagna pasta sheet and pour the stuffing again. Re-apply process for different layers, top it with the stuffing mix.
Put the pan in the oven – preheated at 200° - Bake for 35 minutes
Take out of the oven, cut in portions and serve