In a Dutch oven, heat olive oil and butter. Crisp pancetta, remove. Mince onion, carrots, celery, and garlic in a food processor until paste-like.

Add ground sirloin and Italian sausage in the Dutch oven. Cook until browned, add minced vegetables and sauté until softened.

Stir in tomato paste, cooking until darkened. Add wine, scrape brown bits, and simmer.

Add crushed tomatoes, milk, bay leaves, pancetta, and parmesan rind. Season, simmer for 2.5 to 3 hours.

Cook lasagna noodles in salted water until al dente. Drain and set aside.

Melt butter in saucepan, whisk in flour, and cook. Gradually add warm milk, whisking until thickened.

Layer béchamel, noodles, Bolognese sauce, more béchamel, mozzarella, and parmesan in a greased baking dish.

Preheat oven to 375°F. Bake covered for 1 hour, then uncovered for an additional 15 minutes.

Let the lasagna rest for 20-30 minutes before serving.