In a skillet, heat the olive oil over medium-high heat. Season the beef chuck roast generously with salt and pepper. Once the oil is hot, sear the roast on all sides until browned (about 4-5 minutes per side).
Place the sliced onion, chopped carrots, and quartered potatoes at the bottom of the slow cooker.
In a bowl, mix together the beef broth, Worcestershire sauce, soy sauce, garlic, thyme, and rosemary. Pour this mixture over the vegetables in the slow cooker.
Place the seared beef chuck roast on top of the vegetable mixture. Spoon a bit of the liquid over the roast for added flavor.
Cover the slow cooker and cook on low for 8-10 hours or on high for 4-6 hours, until the meat is fork-tender.
If you prefer a thicker gravy, mix cornstarch with a little water to create a slurry and add it to the slow cooker about 30 minutes before serving.
Once done, carefully remove the roast and vegetables from the slow cooker. Let the roast rest for a few minutes before slicing. Serve the pot roast with the veggies and spoon the delicious broth over the top.
Notes
For a thicker gravy, add a cornstarch slurry 30 minutes before serving.