准备

• In a 2-quart saucepan, bring the broth, peppercorns, and star anise to a boil. Remove from the heat and let steep at least 30 minutes.
• In a 6- to 7-quart heavy-duty pot, melt the butter and olive oil over medium-low heat. Add the carrots, celery, onion, and 1/4 tsp. salt. Cook, stirring occasionally and adjusting the heat as needed, until tender, about 10 minutes.
• Push the vegetables to one side, increase the heat to medium high, and add the lamb. Season the lamb with 1/2 tsp. salt and let briefly sit undisturbed until somewhat browned. Cook, stirring occasionally, to combine with the vegetables, until the lamb no longer looks raw, about 10 minutes.
• Add the wine and tomato paste and stir gently to combine. Simmer until the wine is absorbed, about 3 minutes (the meat will still look wet). Through a fine-mesh sieve, strain 3 cups of the broth into the pot. Add the herb bundle. (Reserve the remaining 1 cup broth.)
• Cook, uncovered, over very low heat, stirring only occasionally, until the sauce has thickened and the flavors are fully developed, at least 2 hours. If the liquid evaporates too quickly, add a little of the reserved broth. Remove the herb bundle; any rosemary leaves in the ragù will have softened and are good to eat. At this point, the sauce can be cooled and refrigerated for up to 3 days or frozen for up to 3 months. Refrigerate or freeze the remaining broth for reheating and serving.
• When ready to serve, reheat the ragù, if necessary; it should be thick and fluid, but not dry. Add more of the reserved broth, if necessary. Bring a pot of well-salted water to a boil and cook the pasta to al dente according to package directions. Reserve 1 cup of the pasta cooking water and drain. Return the pasta to the pot or transfer to a warm bowl. Gently toss the pasta with about 1 cup of the ragù, adding 1/3 cup of the reserved cooking water to moisten the pasta. Add more ragù and pasta water to coat the pasta well.
• Divide the pasta among warm bowls and ladle a small amount of the remaining ragù on top of each. Top with a little olive oil, a sprinkle of cheese, a tiny pinch of the flaky salt, and the greens, if using.