Pat the chuck roast dry with paper towels, then generously season both sides with salt and black pepper. In a large Dutch oven, heat 2 tablespoons of olive oil over medium-high heat. Once shimmering, sear the roast for about 4-5 minutes on each side until deeply browned and caramelized, then remove it from the pot and set aside.

Lower the heat to medium and add the thinly sliced onions to the same Dutch oven. Cook them for 15-20 minutes, stirring frequently, until they are soft, golden, and caramelized. Once the onions are ready, stir in the minced garlic and cook for an additional 1-2 minutes until fragrant.

Sprinkle 2 tablespoons of all-purpose flour over the caramelized onions, stirring to coat evenly. Allow the mixture to cook for 1-2 minutes to remove the raw flour taste. Next, deglaze the pot by pouring in 1 tablespoon of balsamic vinegar, scraping up any browned bits from the bottom, then mix in 2 tablespoons of Worcestershire sauce and 3 cups of beef broth until the gravy begins to thicken slightly.

Return the seared chuck roast to the Dutch oven, nestling it into the flavorful gravy. Surround the beef with the chopped carrots and quartered Yukon gold potatoes. If using, add fresh thyme and rosemary for an aromatic touch. Raise the heat until the mixture comes to a gentle simmer.

Cover the Dutch oven with its lid and transfer it to a preheated oven set at 325°F (165°C). Cook for 3 to 3.5 hours, checking for tenderness; the meat should be fork-tender, and the vegetables should be soft but not mushy.

Once cooked, carefully remove the Dutch oven from the oven and let the roast rest for 10-15 minutes before slicing. Spoon generous amounts of the rich French onion gravy over the sliced beef and plated vegetables for a delightful final touch.