Fill a medium pot with water, add a pinch of salt, and bring to a boil. Add the 12 oz egg noodles and cook according to package instructions until al dente. Drain and set aside, reserving about ½ cup of the pasta water.
In a large pot or deep skillet, heat 2 tablespoons of olive oil over medium heat. Add the diced onion and sauté until translucent and fragrant, about 3-4 minutes. Stir in the minced garlic and cook for another 30 seconds, ensuring it doesn’t brown.
Add the sliced mushrooms to the skillet. Cook, stirring occasionally, until they release their moisture and become golden brown, about 7-8 minutes.
Pour in 1 cup of beef broth and stir in 1 tablespoon soy sauce and 1 teaspoon Dijon mustard. Let the mixture simmer for 5 minutes to reduce slightly and concentrate the flavors.
Lower the heat to medium-low and stir in 1 cup of sour cream. Mix thoroughly until the sauce is creamy and smooth. Adjust seasoning with salt and pepper to taste. If the sauce is too thick, add a splash of reserved pasta water to loosen it.
Add the cooked egg noodles to the skillet and gently toss to coat every strand in the creamy mushroom sauce. Allow the noodles to warm through for 1-2 minutes so the flavors meld perfectly.
Sprinkle chopped parsley over the stroganoff for a pop of color and fresh flavor. Serve immediately and enjoy the comforting, rich taste of Mushroom Stroganoff With Egg Noodles.