Cook the egg noodles according to the package directions. Drain and set aside.
10 ounces egg noodles
While the noodles cook, melt 2 tablespoons of butter in a skillet set over medium-high heat.
4 tablespoons unsalted butter
Add the chicken and season with ½ teaspoon salt and ½ teaspoon pepper. Cook until the chicken is golden and no longer pink. Remove from the skillet and set aside.
1 ½ pounds boneless, skinless chicken breasts, 1 teaspoon salt, 1 teaspoon ground black pepper
Melt the remaining butter in the same skillet. Sauté the onion until translucent, about 5 minutes. Add the mushrooms and cook until softened, about 5-7 minutes.
2 yellow onions, 10 ounces crimini mushrooms
Add the flour and cook for 1-2 minutes, stirring constantly.
¼ cup all-purpose flour
Add the broth, scraping up any brown bits from the bottom of the pan.
2 cups low sodium chicken broth
Stir in the sour cream, mustard, cooked chicken, and remaining salt and pepper. Simmer for 5 minutes until thickened.
⅔ cup sour cream, 1 tablespoon Dijon mustard
Stir in parsley and serve over noodles.
2 tablespoons chopped fresh parsley
Storage: Cream-based recipes don't freeze well and become grainy when thawed and reheated. For best taste and texture, store leftover stroganoff in an airtight container in the refrigerator for up to 3 days.