Preheat your oven to 325 degrees.
Season the chuck roast with kosher salt, black pepper, and thyme.
Heat vegetable oil in a pan until it ripples and is hot, then add the roast and brown deeply for 4-5 minutes on each side.
Add onions and potatoes around the roast.
Combine beef broth, Worcestershire sauce, and thyme; add to the pot.
Cook, covered, for 3 – 3 1/2 hours in the preheated oven.
Remove from the oven, discard thyme sprigs, and gently remove the potatoes and pot roast.
Stir in the heavy cream and 1/3 cup of the blue cheese crumbles. Cook on medium-high heat, whisking until the mixture thickens, about 6-8 minutes.
Return the beef to the pot, breaking it into large chunks.
Serve with potatoes broken in half and covered in blue cheese gravy, sprinkled with remaining blue cheese.