Pulse onion, celery, and carrot in a food processor until very finely chopped. Transfer to a small bowl.
| 1 | onion, chopped |
| 1 | celery stalk, chopped |
| 1 | carrot, peeled and chopped |
Heat oil in a Dutch oven or other large pot over medium heat. Break beef into small clumps (about 1.5 inch) and add to pot; season lightly with salt. Cook, stirring occasionally but not breaking the meat apart, until beef is lightly browned but not crisp, about 6-8 minutes. It may be gray in spots and still a little pink in the center -- that's okay. Using a slotted spoon, transfer beef to a medium bowl.
| 3 tbsp | extra-virgin olive oil |
| 450 g (1 lb) | ground beef chuck (20% fat), patted dry |
| to taste | salt |
Wipe out the pot. Cook pancetta in the pot over medium heat, stirring occasionally, until it has released some of its fat and is crisp, about 6-8 minutes. Add the onion mixture and cook, stirring occasionally, until the vegetables are very soft and beginning to stick to the pot, about 6-8 minutes.
| 85 g (3 oz) | pancetta, thinly sliced and finely chopped |
Return the beef to the pot and pour in the wine. Reduce heat to medium-low and cook, smashing down on the beef with a wooden spoon, until the wine has evaporated, the pot is almost dry, and the meat is finely ground, about 12-15 minutes -- it takes some effort, but you can take breaks. Add the tomato paste, bay leaf, and nutmeg and cook, stirring occasionally and still pressing down on the meat, until the tomato paste has darkened slightly, about 5 minutes.
| 240 ml (1 cup) | dry white wine |
| 85 g (1/3 cup) | tomato paste |
| 1 | bay leaf |
| 1 pinch | nutmeg, finely grated |
Pour in the stock and milk and add a pinch of salt. Reduce heat to the lowest setting and cook, uncovered and stirring occasionally, until the meat is very tender, about 2-2.5 hours. The sauce should release the occasional small bubble, not a rapid boil, and should end up looking like a sloppy joe mixture. If the liquid reduces before the meat is tender, add an extra 1/2 cup of stock and keep cooking. Discard the bay leaf and adjust seasoning with salt.
| 480 ml (2 cup) | chicken stock (or more) |
| 240 ml (1 cup) | whole milk |
| 1 pinch | salt |
Cook the pasta in a large pot of boiling salted water. If using fresh pasta, cook for about 3 minutes; if using dry, cook until very al dente, about 2 minutes less than the package directs.
| 450 g (1 lb) | fresh tagliatelle or pappardelle, or dry rigatoni |
Using tongs, transfer the pasta to the pot with the sauce. Add 1 cup of the pasta cooking liquid and the Parmesan. Increase heat to medium, bring to a simmer, and cook, tossing constantly, until the pasta is al dente and the sauce has thickened slightly, about 2 minutes.
| 57 g (1/2 cup) | parmesan, finely grated, plus more for serving |
Transfer to a platter and top with more Parmesan.