How to Make It
Preheat oven to 300°F. Heat 1/4 cup oil in a large Dutch oven over medium-high. Season chuck roast with salt and pepper. Add chuck roast to Dutch oven, and sear, turning occasionally, until browned on all sides, 15 to 20 minutes. Transfer to a plate, and set aside.
Scrub 1 orange, and cut into 8 wedges; discard seeds and core, and set aside. Add onion to Dutch oven; cook over medium, stirring and scraping bottom of pan often with a wooden spoon, until onion is soft and translucent, about 8 minutes. (Add 1/4 cup water while cooking onion if too many browned bits accumulate.) Add beef stock, tomatoes, 1 chile, and orange wedges; bring to a boil. Return chuck roast and any accumulated juices to pan; bring to a simmer over high.
Cover and transfer to preheated oven; braise 1 hour and 30 minutes. Uncover and stir in sweet potato and celery root. Return to oven, and braise, uncovered, until meat and vegetables are tender but not falling apart, 1 hour to 1 hour and 30 minutes. Remove from oven, and let rest 15 minutes. Transfer chuck roast to a work surface; shred into large pieces. Skim off fat from Dutch oven, and discard. Return shredded beef to Dutch oven.
While meat rests, zest remaining orange to equal 1 tablespoon zest and squeeze to yield 3 tablespoons juice. Finely chop remaining 2 chiles to equal 1 tablespoon. Stir together parsley, orange zest and juice, chopped chiles, and remaining 1/4 cup oil; season with salt and pepper to taste. Divide roast mixture evenly among bowls; top with parsley mixture. Serve with crusty bread.
We like the Tutto Calabria brand of Calabrian chiles.