Heat oil and melt 3 tablespoons butter in a Dutch oven or heavy-bottomed pot, over medium heat. Add the onions, carrots, and celery and sauté for 5-6 minutes, or until the veggies start to soften.
Add the meats and crumble with a wooden spoon. Season with salt and black pepper, and cook for 4-5 minutes, stirring occasionally, until the meats start to brown. Stir in the garlic and cook for 30 seconds. Reduce the heat to low. Pour in the milk and simmer gently, stirring frequently, until most of the milk has cooked out. Stir in the freshly grated nutmeg, and white wine and simmer until evaporated, about 30 minutes.
Add the tomatoes with their juices and parmesan rinds and stir well. When the tomatoes start to bubble, then turn down the heat and simmer uncovered for 3½ hours, stirring from time to time and adding up to ½ cup water, if needed. Remove and discard the parmesan rinds and the herb sprigs. Season to taste with salt and pepper, if desired.
Toss cooked pasta with remaining 2 tablespoons butter and top or mix with the Bolognese sauce. Finish with freshly grated Parmigiano-Reggiano. Enjoy!
