In a large Dutch oven or heavy pot, heat olive oil over medium-high heat. Season beef with salt and pepper. Add beef in batches and sear until browned on all sides. Remove to a plate and set aside.
In the same pot, add the diced onion and cook for 2–3 minutes until softened. Stir in garlic and cook for another 30 seconds until fragrant.
Return beef to the pot. Add beef broth, Worcestershire sauce, thyme, onion powder, and garlic powder. Stir to combine. Bring to a boil, then reduce heat to low, cover, and simmer for 1.5 hours or until beef is tender.
Stir in the egg noodles and simmer uncovered for about 10–12 minutes until the noodles are tender. If you'd like a thicker sauce, stir in the cornstarch slurry and let it simmer another few minutes until thickened.
Taste and adjust seasoning if needed. Garnish with chopped parsley and serve warm.