Bring a large pot of salted water to a boil for the noodles.
Heat olive oil and 1 tablespoon butter in a wide skillet over medium-high heat.
Brown the ground beef, breaking it up as it cooks, until no pink remains. Season with salt and pepper, then transfer to a plate.
Melt the remaining butter in the same skillet. Sauté onion and mushrooms until they release liquid and turn golden, 6–8 minutes.
Stir in garlic and paprika. Cook until fragrant, about 30 seconds.
Sprinkle flour over the vegetables. Stir and cook 1 minute to remove the raw taste.
Whisk in beef broth gradually. Add Worcestershire and Dijon. Simmer, stirring, until the sauce thickens slightly, 3–4 minutes.
Return the browned beef and any juices to the pan. Reduce heat and gently simmer 3–4 minutes to meld flavors.
Cook the noodles until al dente. Drain well.
Take the skillet off heat. Stir in the sour cream until smooth. Adjust salt and pepper to taste.
Toss the noodles with the sauce or serve the sauce spooned over noodles. Finish with parsley.