Heat olive oil in a large skillet over medium heat. Add the ground beef and cook until browned, breaking it apart with a wooden spoon. Set the beef aside.
Add onions and garlic to the same skillet, cooking until the onions are translucent and soft.
Add sliced mushrooms, cooking until softened. Sprinkle flour and stir, followed by beef broth, and Worcestershire sauce. Cook until thickened.
Return beef to the skillet, reduce heat, and stir in sour cream. Allow to blend.
Cook egg noodles as per package instructions. Drain, and serve with the sauce over the noodles, garnished with parsley.
Notes
Store leftovers in an airtight container in the fridge for up to 3 days. Reheat gently on the stovetop.