Heat the oil in a large heavy pot over medium-high heat. Add the soffritto of onions, celery, and carrots. Saut for 6-7 minutes. Add garlic and saut for 1 minute. Place vegetables in a bowl and set aside.
Add ground beef, pork, and bacon; saut, breaking up and turning with a large spoon, until browned. Add the vegetables to the pot and stir.
Add tomato paste, mix well, and heat for 1-2 minutes. Add wine; boil 1 minute, stirring often and scraping up browned bits.
Add 2 cups stock and the roasted pepper, stir to blend. Reduce heat to low and gently simmer, stirring occasionally, until flavors meld, 1.5 hours. Season with salt, pepper, oregano, thyme, and the basil.
Bring milk to a simmer in a small saucepan; gradually add to sauce. Cover pot with lid slightly ajar and simmer over low heat. Stir occasionally until milk is absorbed, about 40 minutes. [Add more stock, 1/4-cupful to thin if needed]
Bring a large pot of water to a boil in another pot. Season with salt and a splash of olive oil. Add pasta and cook, stirring occasionally, until 1 minute before al dente. Drain, reserving 1/2 cup pasta water.
Transfer beef flavored rag to a large skillet over medium-high heat. Add pasta and toss to coat. [Stir in some of the reserved pasta water by the tablespoonful if sauce seems dry] Heat through.
Divide pasta among warm plates and sprinkle with parsley. Serve with Parmesan.
