Pasticcio di maccheroni con la ricotta

• 1 yellow onion
• 1 carrot
• 1 celery rib
• 1

Chop together finely the onion, carrot, and celery. Tie the meat with kitchen string so it will keep its shape. Put it in a saucepan with 3 tablespoons of the oil and brown uniformly over medium heat for about 5 minutes. When a crust has formed on the surface, add the chopped vegetables and sauté fo