01 - Heat olive oil in a large heavy-bottomed pot over medium heat. Add onion, carrots, and celery; sauté for 6 to 8 minutes until softened.
02 - Incorporate minced garlic and cook for 1 minute until fragrant.
03 - Increase heat to medium-high, add ground beef breaking it apart with a spoon, and cook until browned and no longer pink, about 8 minutes.
04 - Stir in tomato paste and cook for 2 minutes. Pour in red wine, scraping browned bits from the pot bottom. Simmer until the wine has mostly evaporated, about 3 minutes.
05 - Add crushed tomatoes, beef stock, whole milk, bay leaves, oregano, thyme, salt, and pepper. Stir thoroughly and bring to a gentle simmer.
06 - Reduce heat to low, partially cover, and cook for 1 to 1.5 hours, stirring occasionally, until sauce thickens and flavors deepen. Add extra stock if sauce thickens excessively.
07 - Remove bay leaves, taste, and adjust seasoning as needed.
08 - While sauce simmers, bring salted water to a boil in a large pot. Cook tagliatelle following package directions until al dente. Drain, reserving 1/2 cup of pasta water.
09 - Toss tagliatelle with a ladle of Bolognese and some reserved pasta water. Serve topped with additional sauce and grated Parmigiano-Reggiano. Garnish with basil or parsley if desired.