In a large pot of salted boiling water, cook the egg noodles according to package instructions. Drain and return to the pot.

Heat 1 tablespoon of olive oil in a large skillet over medium-high heat. Slice the beef into thin strips and season with salt and pepper. Add half of the beef to the skillet and sear until browned, about 3 minutes. Remove and repeat with the remaining beef.

In the same skillet, add the remaining tablespoon of olive oil, then add the chopped onion and cook for 2 minutes until translucent. Introduce the minced garlic and sliced mushrooms, sautéing until mushrooms are tender, about 5 minutes.

Sprinkle flour over the vegetables and stir well to coat. Gradually add the beef broth while stirring, ensuring there are no lumps. Bring to a gentle simmer and cook for 2-3 minutes, allowing the sauce to thicken.

Lower the heat and return the cooked beef to the skillet. Stir in the sour cream until evenly incorporated. Warm through but do not boil (this prevents the sour cream from curdling). Adjust seasoning to taste.

Pour the beef stroganoff over the cooked egg noodles and mix gently. Garnish with fresh parsley if desired.