Preheat the oven to 300°F (150°C).
Pat the chuck roast dry and season generously with kosher salt. If possible, season at least 30 minutes ahead or overnight.
Heat the olive oil in a large Dutch oven over medium high heat. Sear the roast on all sides until deeply browned. Remove and set aside.
Reduce the heat to medium. Add the onion and cook for 5 to 7 minutes, until softened.
Add the smashed garlic and cook for 30 seconds. Stir in the fennel seed and cook for 30 to 60 seconds.
Add 2 teaspoons olive oil and the fresh oregano and thyme. Cook for about 1 minute to release their aroma.
Pour in the white wine and scrape up any browned bits from the bottom of the pot. Simmer for 2 to 3 minutes.
Return the roast to the pot. Add the lemon zest, lemon juice, and chicken broth. The liquid should come about halfway up the sides of the meat. Add the rosemary sprig, if using. Cover the pot and bring the liquid to a gentle boil.
Transfer the Dutch oven to the oven and cook for 3 hours. Near the end of the cooking time, remove the lid and let the roast develop a bit of a crust, about 20 more minutes.
Remove from the oven, cover again, and allow the roast to rest for at least 30 minutes before slicing or shredding.