1. Heat the oil in a saucepan. Add and sauté the onion. Add the carrot, celery, lentils, water, garlic.
2. Season with salt and pepper, cover, bring to a boil, then simmer for about 20 minutes, until all the water is absorbed.
3. Add the breadcrumbs, 3/4 of the cheese, parsley, and egg.
4. Pour into a baking dish. Sprinkle with sesame seeds, the remaining cheese, and bake for 45 minutes at medium heat (180°C).
5. Serve with tomato sauce, potatoes, and a green salad (optional).