Bring a large pot of salted water to a boil. Cook the egg noodles until tender according to the package directions. Drain and set aside.
Pat the beef dry and season with salt and pepper. Heat 1 tablespoon oil in a large skillet over high heat. Brown the beef in a single layer in batches, about 1 minute per side; transfer to a plate. The beef will finish cooking in the sauce.
Lower heat to medium and add the remaining oil. Cook the onion and mushrooms until softened and browned, 6 to 8 minutes. Stir in the garlic for 30 seconds, then sprinkle flour over the vegetables and cook for 1 minute.
Gradually stir in the beef broth, scraping the skillet. Add Worcestershire and Dijon. Bring to a gentle simmer and cook until the sauce thickens, about 5 minutes.
Return the beef and any juices to the skillet and simmer just until cooked through, about 2 to 3 minutes. Remove from heat. Stir a few spoonfuls of hot sauce into the sour cream, then fold the mixture into the skillet. Do not boil after adding sour cream.
Taste and adjust seasoning. Serve over egg noodles with parsley.