01 - Bring a large pot of salted water to a rolling boil. Add the 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 the ground beef and cook until fully browned, breaking it apart with a wooden spoon. Remove the beef with a slotted spoon and set aside, leaving the drippings in the pan.
03 - In the same skillet, add the diced onion and cook for 3 to 4 minutes until softened. Add the sliced mushrooms and cook for an additional 5 minutes until golden brown. 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. Add the Worcestershire sauce and Dijon mustard. Bring the mixture to a gentle simmer and cook for 5 minutes until the sauce has slightly thickened.
06 - Return the browned beef to the skillet and stir to combine. Reduce the heat to low, then gently fold in the sour cream until the sauce is smooth and creamy. Season with salt and black pepper to taste.
07 - Add the cooked egg noodles to the skillet and toss gently until evenly coated with the stroganoff sauce. Serve immediately, garnished with fresh chopped parsley if desired.