Season the Chuck Roast: Pat the beef chuck roast completely dry with paper towels. Season generously on all sides with kosher salt, cracked black pepper, garlic powder, and onion powder.

Sear for Maximum Flavor: Heat 2 tablespoons of olive oil in a large heavy skillet or Dutch oven over medium-high heat. Sear the seasoned roast for 4 to 5 minutes per side until a deep, dark golden-brown caramelized crust forms. Transfer the seared roast directly into the slow cooker basin.

Deglaze the Skillet: Pour 1/2 cup of the beef broth into the hot skillet, scraping up all the savory browned bits (fond) from the bottom of the pan. Whisk in the remaining beef broth, Worcestershire sauce, tomato paste, and soy sauce until smooth.

Assemble Vegetables & Herbs: Scatter the thick yellow onion wedges, halved baby Yukon gold potatoes, baby carrots, and smashed garlic cloves around and atop the chuck roast in the slow cooker. Pour the warm seasoned broth mixture evenly over everything. Tuck the fresh rosemary, thyme sprigs, and bay leaf into the liquid.

Slow Cook to Tender Perfection: Cover with the lid and cook on LOW for 8 to 9 hours (or on HIGH for 4 to 5 hours). The pot roast is done when the meat is melt-in-your-mouth fork-tender and pulls apart effortlessly.

Thicken into Luxurious Rich Gravy: Transfer the tender roast and vegetables to a warm serving platter and tent loosely with foil. Pour 2 cups of the warm cooking juices from the slow cooker into a small saucepan over medium heat. Whisk in the cornstarch slurry and simmer for 2 to 3 minutes until thickened into a glossy, velvety gravy. Season with salt and pepper to taste.

Shred & Serve: Shred the beef into large, juicy succulent pieces. Spoon the rich hot gravy generously over the shredded pot roast and vegetables. Garnish with chopped fresh parsley and serve immediately!