One of northern Italy’s most beloved pasta sauces, ragù Bolognese develops its famous depth of flavor over hours of slow simmering. Like a fine Cabernet Sauvignon, it can’t be rushed. Its richness and creamy sweetness call for the chewy tannins of a youthful Cabernet Sauvignon, such as a recent vintage of Rutherford.
In a food processor, pulse the carrot, celery, onion, and garlic into small pieces.
Heat the olive oil in large, heavy-bottomed Dutch oven over medium heat. Add the vegetables and sauté until softened but not browned.
Add the pancetta, ground meats, and a pinch of salt, and use a wooden spoon to break the ground meats into small pieces. Sauté, continuing to break up the meat, just until it is lightly browned.
Add the milk, bring to a simmer, and continue to simmer until the milk evaporates and only clear fat remains.
Add the stock, bring to simmer, and continue to simmer for 10 to 15 minutes.
Add the tomatoes, bring to a simmer, and reduce the heat to low so that sauce continues to simmer just barely with an occasional bubble or two at the surface. Cook uncovered, or partially covered, until the liquid has evaporated, 2 to 3 hours. Adjust the seasoning with salt.
Transfer the ragù to a large sauté pan and keep warm.
Bring a large pot of salted water to a boil. Add the pasta, stir gently, and cook until al dente.
Transfer the pasta to the warm ragù and combine. Add pasta cooking water if needed to achieve a saucelike consistency.
Serve with a sprinkling of Parmigiano-Reggiano.