Begin by trimming any excess fat from the beef roast. Cut the beef into large chunks.
In a large skillet, heat the olive oil over medium-high heat. Sear the beef chunks on all sides until browned, about 5-7 minutes. (This step is optional but adds extra flavor.)
Place the beef in the slow cooker. Add the diced onion, minced garlic, beef broth, sliced carrots, sliced celery, thyme, rosemary, salt, black pepper, and Worcestershire sauce. Stir to combine.
Cover the slow cooker and cook on low for 8 hours or until the beef is fork-tender.
About 30 minutes before serving, cook the egg noodles according to package instructions and drain.
Once the beef is done, shred it with two forks directly in the slow cooker and mix it with the sauce and vegetables.
Serve the beef mixture over the cooked egg noodles. Garnish with fresh parsley if desired.