- In a large pot of boiling salted water, cook pasta 11 min or until al dente. Drain well, then return to pot. Meanwhile, melt 1 Tbsp (15 mL) butter in a large saucepan over medium heat. Add onion, carrot and celery, cook 2 min. Add beef and garlic. Using a fork to break up meat, stir until no longer pink, about 5 min. Add tomatoes, herbs, 1∕2 tsp (2 mL) salt and pepper. Bring to a boil; simmer covered, stirring occasionally, for 10 min while preparing white sauce.
- Melt remaining butter in a small saucepan over medium heat. Sprinkle with flour and remaining salt. Whisk about 1 min. Gradually whisk in milk. Bring to a boil then reduce heat; whisk 3 to 5 min until smooth and thickened.
- Preheat broiler. Uncover meat sauce and simmer 5 more min. Discard bay leaf. Add meat sauce to drained pasta. Heat if needed. Transfer to a 9 x 13-inch (3 L) casserole dish. Top with dollops of ricotta. Drizzle white sauce over top, spread, if needed, to cover. Sprinkle with mozzarella. Broil 2 to 5 min or until cheese is bubbly.
Cooking tip: As with all sauces, make them your own. Taste and adjust seasoning to your preferences.