Over medium heat, melt 3 Tbsp of the butter and olive oil in a large pot. Add the chopped onion, and stir until it has become translucent, then add the Aglio Napoletano, celery and carrot. Cook for about 2 minutes, stirring well.
Add ground beef and pork and a generous pinch of salt. Separate the meat with a wooden spoon and cook until the meat is a light brown color.
Add the milk and let it simmer gently, stirring frequently for about 2 minutes.
Add the wine, simmering until it has evaporated, then add the tomatoes and juice. Stir until the mixture begin to bubble, then lower the heat low. Cook uncovered, for 3 hours or more, stirring occasionally. If the sauce thickens too much, add ¼ cup of water at a time during cooking.
Serve with pasta, and top generously with Parmigiano-Reggiano.
