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 well 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, breaking it apart with a wooden spoon, 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. Stir in the sliced mushrooms and continue cooking for about 5 minutes until golden brown. Add the minced garlic and sauté for 1 minute until fragrant.
04 - Add the butter to the skillet and let it melt into the vegetables. Sprinkle in the flour and stir constantly for 1 to 2 minutes to cook out the raw flour taste and form a light roux.
05 - Gradually pour in the beef broth while whisking continuously to prevent lumps from forming. Stir in the Worcestershire sauce and Dijon mustard. Bring the mixture to a simmer and cook for about 5 minutes until the sauce has slightly thickened.
06 - Return the browned beef to the skillet and stir to incorporate. 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 drained egg noodles to the skillet and toss gently until evenly coated with the stroganoff sauce. Serve immediately, garnished with chopped fresh parsley if desired.