01 - Season the chicken strips thoroughly with salt and pepper on all sides.
02 - Heat 1 tbsp butter and olive oil in a large skillet over medium-high heat. Add chicken and sauté until golden brown and cooked through, approximately 5–7 minutes. Transfer to a plate and reserve.
03 - Add remaining 1 tbsp butter to the pan. Sauté onion 2–3 minutes until translucent. Add mushrooms and cook until browned and liquid has evaporated, about 5 minutes. Stir in garlic and cook 1 minute until fragrant.
04 - Sprinkle flour over vegetables, stirring constantly to coat evenly. Cook 1 minute to remove raw flour taste.
05 - Gradually whisk in chicken broth, followed by Dijon mustard, paprika, and Worcestershire sauce. Simmer 3–4 minutes until slightly thickened.
06 - Reduce heat to low. Stir in sour cream until fully incorporated and smooth. Return chicken with accumulated juices to skillet. Simmer gently 2–3 minutes until heated through. Do not boil.
07 - Taste sauce and adjust salt and pepper as needed.
08 - Garnish generously with fresh parsley. Serve immediately over egg noodles, rice, or mashed potatoes.