Pappardelle with Duck and Chestnut Ragù

Adjust oven rack to middle position and heat oven to 300 degrees. Pulse chestnuts in food processor until finely chopped, 10 to 12 pulses, scraping down sides of bowl as needed; transfer to bowl. Pulse onion, carrot, and celery in now empty processor until finely chopped, 10 to 12 pulses; set aside.

Using metal skewer, poke 15 to 20 holes in skin of each duck leg quarter, then pat dry with paper towels. Place duck skin side down in dutch oven and cook over medium heat until well browned on first side and fat has rendered, 15 to 20 minutes. Flip duck and continue to cook until well browned on each side, about 3 minutes; transfer to plate. Pour off and reserve all but 2 tablespoons fat from pot.

Add vegetable mixture and salt to fat left in pot and cook over medium heat until vegetables are softened, 5 to 7 minutes. Stir in 1 teaspoon rosemary and cook until fragrant, about 30 seconds. Stir in wine, scraping up any browned bits, and cook until reduced slightly, about 1 minute.

Stir in broth and half of chestnuts. Nestle duck into pot with any accumulates juices and bring them to simmer. Cover, transfer pot to oven, and cook until duck is very tender and falling off bones, about 2 hours.

While duck cooks, heat 1 tablespoon reserved fat in 10-inch skillet over medium heat until shimmering (discard remaining fat or reserve for another use). Add panko and cook, stirring frequently, until light golden brown, 2 to 3 minutes. Stir in remaining chestnuts and remaining ½ teaspoon rosemary and cook until fragrant and deep golden brown, about 2 minutes; set aside.

Remove pot from oven. Transfer duck to cutting board, let cool slightly, then shred meat into bite-size pieces using 2 forks; discard skin and bones. Bring sauce to simmer over medium-high heat and cook until thickened slightly, 3 to 5 minutes, stir in shredded meat and vinegar and season with salt and pepper to taste.

Meanwhile, bring 4 quarts water to boil in large pot. Add pasta and 1 tablespoon salt and cook, stirring often, until dente. Reserve ½ cup cooking water, then drain pasta and return it to pot. Add sauce and toss to combine. Adjust consistency with reserved cooking water as needed. Season with salt and pepper to taste. Sprinkle individual partitions with chestnut-panko mixture before serving.