01 - Preheat oven to 325°F.
02 - Pat the beef dry with paper towels and season evenly with kosher salt and freshly ground black pepper.
03 - Heat olive oil in a large Dutch oven over medium-high heat. Sear the roast on all sides until deeply browned, approximately 4–5 minutes per side. Remove beef and set aside.
04 - Reduce heat to medium. Add butter and sliced onions to the pot. Cook, stirring frequently, 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 form a roux.
06 - Pour in white wine, scraping up any browned bits from the bottom of the pot. Simmer until wine is reduced by half, approximately 2 minutes.
07 - Return the roast to the pot. Add beef broth, Worcestershire sauce, thyme sprigs, and bay leaf. Arrange carrots and potatoes around the beef.
08 - Bring liquid to a simmer, cover tightly with lid, and transfer to the preheated oven. Braise for 2.5 to 3 hours, or until beef is fork-tender.
09 - Remove roast and vegetables from the pot. Discard thyme stems and bay leaf. Skim excess fat from the surface of the sauce. Simmer on stovetop over medium heat if additional thickening is desired.
10 - For a classic French onion presentation, sprinkle grated Gruyère cheese over the roast and broil until melted and bubbly.
11 - Slice or shred the beef against the grain. Serve with vegetables and gravy, garnished with chopped fresh parsley.