Start by cooking the egg noodles according to package instructions. Once cooked, drain and set aside.
In a large skillet over medium heat, add the olive oil. Once hot, add the diced onion and cook for about 3 minutes until it begins to soften.
Add the sliced mushrooms to the skillet and cook for an additional 5 minutes until they are tender.
Add the minced garlic and ground beef to the skillet. Cook until the beef is browned, breaking it up with a spatula as it cooks, about 5-7 minutes. Drain excess fat if necessary.
Stir in the beef broth, Worcestershire sauce, and Dijon mustard. Bring the mixture to a simmer.
Reduce the heat to low and stir in the sour cream. Mix well until the sauce is heated through. Season with salt and pepper to taste.
Add the cooked noodles to the skillet and gently toss until everything is well combined and coated with the creamy sauce.
Serve hot, garnished with fresh parsley if desired.