Start by patting the beef chuck roast dry with paper towels, ensuring it's moisture-free for better browning. Generously season all sides with salt and black pepper.

In a Dutch oven, heat olive oil over medium-high heat. Add the seasoned beef and sear each side for approximately 4-5 minutes until a golden-brown crust forms.

In the same pot, add chopped onions and sauté for about 5-6 minutes until softened. Then add minced garlic and cook for an additional minute.

Pour in balsamic vinegar to deglaze the pot, scraping up browned bits. Let the vinegar simmer for 2-3 minutes to intensify the flavor.

Stir in beef broth and brown sugar, mixing well until the sugar dissolves. Return the browned roast to the pot.

Add cranberries and fresh thyme around the roast. Optionally, include halved carrots.

Cover the Dutch oven and transfer it to a preheated oven at 325°F. Cook for 3 to 3.5 hours, until fork-tender.

After cooking, let the roast rest for 10 minutes to allow juices to redistribute.

Slice or shred the roast and serve atop a bed of the rich glaze.