Line a plate with paper towels; set aside. Heat the oil in a large, heavy bottom pot or Dutch oven over medium heat. When the oil shimmers, add the pancetta and cook until crisp, about 6 minutes. If the pancetta lets off a lot of fat, discard all but 3 tbsp of drippings. Remove the pancetta with a slotted spoon to the prepared plate and set aside.

Return the pot to the stove over medium heat, add the onion and garlic, season with salt and pepper, and cook until vegetables are translucent, about 5 minutes. Add the carrots, celery and bay lead and cook until tender, about 5 minutes.

Add the ground meat and stir to break up. Once the meat starts to brown, after about 10 minutes, add the tomato paste and stir until evenly mixed. Add the wine, tomato puree, and the diced tomatoes with juice and cook until the tomatoes start to simmer, about 10 minutes,

Add the milk, 1 tbsp kosher salt, and butter and mix until thoroughly incorporated and bring to a simmer. Decrease the heat to very low, and simmer, uncovered, stirring occasionally, until the sauce is thick and reduced by about one-third, about 1 1/2 - 2 hours. Taste the sauce and add the sugar if the sauce is sour. Stir in the reserved pancetta, sliced basil and cheese; tate, and adjust seasoning as needed.