Heat the olive oil in a heavy casserole over medium-high heat. Add the meat, season with salt and pepper, and brown until deeply caramelised on all sides.
Reduce the heat to low. Add the celery, carrot, and onion, stirring to coat in the fat. Drop in the rosemary, sage, and bay leaves (and a pinch of nutmeg, if using). Cover and let the vegetables sweat gently for a few minutes.
Stir in the tomato paste, then pour in the red wine. Turn the heat to its lowest setting, cover, and move the pot to the smallest burner.
Simmer very gently for about 2 hours. Check occasionally; if the pot looks dry, add a splash of water and stir to prevent sticking.
The ragu is ready when the meat pulls away from the bone with a fork. If it still feels tough, continue cooking until tender.
Cook your pasta in salted water. Off the heat, toss with the ragu and finish with plenty of Parmigiano Reggiano.