Trim any large fat pieces from the roast and cut into 1 inch cubes.
Add oil to a large pot or dutch oven over high heat. Season beef on all sides with salt and pepper.
Once oil is hot, add beef to the pot and sear on all sides.
Stir in beef broth, onion soup mix, rosemary, thyme, and garlic cloves. Bring mixture to a boil, then reduce heat to low, cover and cook for 1 hour.
Add mushroom soup, celery and carrots and cook for another 20 minutes. Add egg noodles and cook for 5-10, minutes, until tender. Stir in sautéed mushrooms before serving, if desired.
Leftover soup will keep in the refrigerator for 3-4 days.
