Set a large pot or Dutch oven over medium high heat. Add the olive oil and butter until melted; swirl the pan. Add the mushrooms and garlic and sauté, stirring occasionally, for 5 to 8 minutes or until the liquid has evaporated. Season with salt and pepper to taste, and transfer to a bowl or plate; set aside.
Return the pot to the heat and add the ground beef. Cook until no longer pink, breaking apart and stirring as the meat cooks; drain the grease. Reduce the heat to medium and stir in the garlic powder, onion powder, and Worcestershire sauce. Sprinkle the flour over the beef and cook for 1 minute, stirring continuously. Add the beef broth to the pot, stir to combine, bring to a boil, and reduce to a simmer. Cook for 5 minutes or until thickened. Add the mushrooms back to the pot along with the sour cream and half of the parsley. Stir to combine, adjust the salt and pepper to taste, and cook for a few more minutes until heated through.
Serve over hot egg noodles garnished with additional chopped parsley.