In a heavy-bottom 8-quart pot, heat oil (2 tablespoons) and butter (2 tablespoons). Add onions (1 1/2 cups), celery (4 ribs), carrots (4), garlic (1 heaping), 1/2 teaspoon salt, and 1/4 teaspoon black pepper then sauté, on medium-high, stirring often, until vegetables are tender and translucent, about 8-10 minutes.
Add the ground beef (1 pound), ground pork (1 pound), pancetta (4 ounces), 1 1/2 teaspoon salt, and 1/2 teaspoon black pepper. Turn the heat up to high, then brown and crumble the meats.
When meat is browned, stir in tomato paste (1 can), lower the heat to medium, and continue to cook for 10-15 minutes.
Pour in the milk (1 cup) then continue to cook for 2-3 minutes.
Stir in wine (1 cup), canned whole tomatoes (1 can) and their liquid (breaking them up with your hands as you add them, discarding hard stem core), and Parmesan rind, then bring mixture to a boil.
Reduce the heat to low, stir in fresh rosemary (1 sprig), oregano (3-4 sprigs), and sage (1/4 cup), then simmer, uncovered, for 2 to 3 hours. Stir occasionally, watching so as not to burn the sauce. If the sauce begins to look dry, pour in 1/4 cup of water, as frequently as needed.
After the sauce is done simmering, stir in 1/4 cup heavy cream. Continue to simmer gently, for 5 minutes. Taste and adjust seasoning adding more salt and pepper. Remove and discard any herb stems and Parmesan rind.