1. Heat 1 tablespoon butter in a large skillet over medium heat. Add the chicken pieces and cook until browned and cooked through. Remove from skillet and set aside.

2. In the same skillet, add remaining butter, onions, and mushrooms. Sauté until softened and golden, about 5 minutes.

3. Add the garlic and cook for another 30 seconds, stirring constantly to prevent burning.

4. Sprinkle flour over the mushroom mixture and stir to coat. Slowly pour in the chicken broth while whisking to avoid lumps.

5. Bring the mixture to a simmer and cook until slightly thickened, about 4–5 minutes.

6. Reduce the heat and stir in sour cream, Dijon mustard, and paprika until smooth. Season with salt and pepper.

7. Return the cooked chicken to the skillet and stir to coat in the sauce. Let it simmer for another 3–5 minutes until everything is heated through.

8. Garnish with fresh parsley and serve over noodles, mashed potatoes, or rice.