Preheat oven to 350 degrees.
Season both is sides of beef roast with salt and pepper. Coat both side with flour.
In a oven safe cast iron pan, add olive oil. When oil is hot, add beef roast and brown on both sides.
Remove beef roast from the pan and place on a plate. Add carrots, celery, and onion and cook until charred, about 3-5 minutes. Add garlic and let cook for about 2 minutes.
Remove vegetables from the pan. Add tomato paste, beef broth and Worcestershire and bring to a boil while scraping the bottom of the pan to remove the brown bits.
Add beef back to the pan and place the vegetables, potatoes, rosemary and thyme around the beef then cover. Place into preheated oven and bake for 2 hours or until beef is easily shredded with a fork.