01 - Heat olive oil in a large, heavy-bottomed pan over medium heat. Sauté onion, carrot, and celery for 7 to 8 minutes until soft and translucent.
02 - Stir in minced garlic and cook for 1 minute, stirring frequently.
03 - Increase heat to medium-high, add ground beef, and cook until browned, breaking it up with a spoon for 6 to 8 minutes.
04 - Stir in tomato paste and cook for 2 minutes to deepen the flavor.
05 - Pour in red wine and simmer for 2 to 3 minutes, scraping up any browned bits.
06 - Add crushed tomatoes, oregano, basil, bay leaf, salt, and pepper. Bring mixture to a gentle simmer.
07 - Reduce heat to low, cover partially, and simmer for 50 to 60 minutes, stirring occasionally.
08 - Stir in milk and continue simmering for another 10 minutes. Adjust seasoning if necessary.
09 - Meanwhile, cook spaghetti in a large pot of salted boiling water according to package instructions until al dente. Drain thoroughly.
10 - Remove bay leaf from sauce. Toss spaghetti with a portion of the sauce or plate spaghetti and ladle sauce generously atop. Garnish with Parmesan cheese and fresh basil if desired. Serve immediately.