Cook the noodles:
Bring a large pot of salted water to a boil. Add the egg noodles and cook according to package instructions. Drain and set aside.
Brown the ground beef:
Heat olive oil in a large skillet over medium heat. Add the ground beef and cook, breaking it apart with a spoon, until browned and cooked through. Season with salt and pepper. Remove the beef from the skillet and set aside.
Cook the vegetables:
In the same skillet, add the onions and sauté for 2–3 minutes until soft. Add the garlic and mushrooms, cooking for an additional 4–5 minutes until the mushrooms are tender.
Make the sauce:
Sprinkle the flour over the vegetables and stir well. Gradually add the beef broth, stirring constantly to prevent lumps. Bring to a simmer and let it thicken, about 2–3 minutes.
Add the creamy elements:
Stir in the sour cream, Dijon mustard, and paprika. Return the cooked ground beef to the skillet and stir to combine. Simmer for 2–3 minutes to heat through.
Combine and serve:
Add the cooked egg noodles to the skillet and toss to coat them in the creamy sauce. Garnish with fresh parsley if desired, and serve immediately.