Prepare the Flavor Base: Heat the olive oil in a large Dutch oven or heavy-bottomed pot over medium heat. Add the onion, carrot, celery, and garlic, cooking until softened and golden, about 5 to 7 minutes. Stir occasionally to ensure even browning without burning.
Brown the Meats: Add the ground beef, pork, and pancetta to the pot. Break the meat apart with a wooden spoon and cook until lightly browned, approximately 5 to 7 minutes. Allow the mixture to develop color and depth for a richer flavor profile.
Incorporate the Tomato Paste and Spices: Stir in the tomato paste and chili flakes, mixing well to coat the meat evenly. Continue to cook for 2 minutes, allowing the tomato paste to caramelize slightly and intensify in flavor.
Deglaze with Wine: Pour in the wine, stirring to deglaze the pot and release any browned bits from the bottom. Simmer until the wine reduces almost completely, about 8 to 10 minutes, leaving behind a robust and aromatic base.
Add the Milk: Pour in the milk and simmer gently until it has mostly evaporated, approximately 8 to 10 minutes. This step softens the acidity of the tomatoes and enhances the sauce’s creaminess.
Simmer the Sauce: Add the crushed tomatoes, chicken broth, bay leaves, Italian seasoning, salt, and a light pinch of black pepper. Stir well to combine, then bring the mixture to a gentle simmer. Reduce the heat to low and allow the sauce to cook slowly for 1 to 3 hours, stirring occasionally. The sauce should thicken, deepen in color, and develop a luxurious texture.
Adjust Consistency and Seasoning: If the sauce reduces too much during cooking, add ¼ cup of hot water or broth at a time as needed. Taste the sauce and adjust the seasoning with additional salt or pepper if required.
Finish with Cheese and Herbs: Once the sauce reaches the desired consistency, stir in the grated Parmesan cheese and fresh parsley. Fold gently until combined, allowing the cheese to melt into the sauce for a silky finish.
Serve the Sauce: Serve generously over your choice of pasta — spaghetti, tagliatelle, fettuccine, or rigatoni. For optimal results, toss the cooked pasta directly into the sauce, adding a splash of reserved pasta water to help it adhere. Finish with additional Parmesan and fresh herbs before serving.