01 - Bring a large pot of salted water to a boil. Cook egg noodles according to package directions until al dente. Drain thoroughly and set aside.
02 - Melt butter in a large skillet over medium-high heat. Add onions and cook 2-3 minutes until softened. Add mushrooms and cook 4-5 minutes until they release moisture and begin to brown.
03 - Stir in minced garlic and cook for 30 seconds, stirring constantly to prevent burning.
04 - Add ground beef to the skillet. Cook, breaking apart with a wooden spoon, until browned and completely cooked through, approximately 5-7 minutes. Drain excess fat if needed.
05 - Sprinkle flour evenly over the meat mixture. Stir thoroughly to coat all ingredients. Cook for 1 minute to eliminate raw flour flavor.
06 - Gradually pour in beef broth, Worcestershire sauce, and Dijon mustard. Bring to a gentle simmer while scraping up browned bits from the pan bottom. Season with salt and pepper.
07 - Reduce heat to low and simmer for 5-7 minutes until sauce achieves desired consistency.
08 - Remove skillet from heat. Stir in sour cream until completely incorporated and sauce becomes smooth and creamy.
09 - Taste the stroganoff and adjust salt and pepper as needed.
10 - Spoon the stroganoff over prepared egg noodles. Garnish with fresh parsley if desired and serve immediately.