Season the beef cubes with salt and black pepper.
Heat olive oil in a large skillet over medium-high heat. Add the beef cubes in batches and brown on all sides, about 3-4 minutes per batch. Transfer browned beef to the crock pot.
In the same skillet, add diced onion and cook until softened, about 3 minutes. Add minced garlic and cook for 30 seconds until fragrant. Transfer onion and garlic to the crock pot.
Add beef broth, Worcestershire sauce, dried thyme, dried rosemary, and bay leaves to the crock pot. Stir to combine.
Add sliced carrots and celery to the crock pot.
Cover and cook on low for 6 hours, or until the beef is tender.
About 20 minutes before serving, bring a large pot of salted water to a boil. Cook egg noodles according to package instructions until al dente. Drain and toss with unsalted butter.
Once the beef is tender, remove bay leaves from the crock pot.
To thicken the sauce, whisk together all-purpose flour and cold water until smooth. Stir the mixture into the crock pot. Cover and cook on high for 15 minutes until sauce thickens.
Serve the beef and vegetables over the buttered egg noodles. Garnish with chopped fresh parsley.