01 - Preheat oven to 325°F.
02 - Pat the beef dry with paper towels and season generously with kosher salt and freshly ground black pepper on all sides.
03 - Heat olive oil in a large Dutch oven over medium-high heat. Sear the roast on all sides until deeply browned, about 4–5 minutes per side. Remove beef and set aside.
04 - Reduce heat to medium. Add butter and sliced onions. Cook, stirring often, until onions are deeply caramelized and golden brown, about 20–25 minutes.
05 - Stir in minced garlic and cook for 1 minute until fragrant. Sprinkle flour over the onions and cook, stirring constantly, for 2 minutes to remove raw flour taste.
06 - Pour in white wine, scraping up any browned bits from the bottom of the pot with a wooden spoon. Cook until wine is reduced by half, about 2 minutes.
07 - Return the roast to the pot. Add beef broth, Worcestershire sauce, thyme sprigs, and bay leaf. Arrange carrots and halved potatoes around the roast.
08 - Bring to a simmer, cover tightly with lid, and transfer to the oven. Braise for 2.5–3 hours, or until beef is fork-tender and easily shreds.
09 - Remove roast and vegetables to a platter. Discard thyme stems and bay leaf. Skim excess fat from the sauce, then simmer on stovetop if needed to thicken further.
10 - For a classic French onion finish, sprinkle grated Gruyère cheese over the roast and broil until melted and bubbly.
11 - Slice or shred the beef and serve with vegetables and gravy. Garnish with chopped fresh parsley.