01 - Bring a large pot of salted water to a rolling boil. Add egg noodles and cook according to package directions until al dente. Drain thoroughly and set aside.
02 - While the noodles cook, heat olive oil in a large skillet over medium-high heat. Add ground beef, breaking it apart with a wooden spoon, and cook until fully browned and no pink remains. Transfer the beef to a plate using a slotted spoon and set aside.
03 - In the same skillet, add the diced onion and cook for 3 to 4 minutes until softened. Add the sliced mushrooms and continue cooking for 5 minutes until deeply browned. Stir in the minced garlic and sauté for 1 minute until fragrant.
04 - Add the butter to the skillet and allow it to melt completely. Sprinkle in the flour and stir continuously for 1 to 2 minutes to form a light roux and cook off the raw flour taste.
05 - Gradually pour in the beef broth while stirring constantly to prevent lumps from forming. Stir in the Worcestershire sauce and Dijon mustard. Bring the mixture to a simmer and cook for 5 minutes until the sauce has slightly thickened.
06 - Return the browned beef to the skillet and reduce the heat to low. Gently stir in the sour cream until fully incorporated and the sauce is smooth. Season with salt and black pepper to taste.
07 - Add the drained egg noodles to the skillet and toss gently to coat evenly with the stroganoff sauce. Serve immediately, garnished with chopped fresh parsley if desired.