Preheat oven to 325°F (165°C).
Heat olive oil in a large Dutch oven over medium-high heat and sear the chuck roast on all sides until browned.
Remove roast and set aside.
In the same pot sauté sliced onions until soft and lightly caramelized.
Add minced garlic and cook for about 1 minute until fragrant.
Pour in beef broth, French onion soup mix, Worcestershire sauce, thyme, salt, and pepper and stir well.
Return the seared roast to the pot and spoon some onions and broth over the top.
Cover with a lid and transfer to the oven.
Bake for about 3 hours until the meat is tender and easily shreds with a fork.
If desired sprinkle shredded cheese over the roast during the last 5 minutes of cooking.
Remove from oven, garnish with parsley, and serve with the rich onion gravy.