01 - Season the chicken strips with salt and pepper evenly.
02 - Heat 1 tbsp butter and olive oil in a large skillet over medium-high heat. Add chicken and sauté until golden and cooked through, about 5–7 minutes. Transfer to a plate and keep warm.
03 - Add remaining 1 tbsp butter to the pan. Sauté onion for 2–3 minutes until translucent. Add mushrooms and cook until browned and liquid has evaporated, about 5 minutes. Stir in garlic and cook for 1 minute.
04 - Sprinkle flour over vegetables, stirring to coat evenly, and cook for 1 minute.
05 - Gradually whisk in chicken broth, then add Dijon mustard, paprika, and Worcestershire sauce. Simmer for 3–4 minutes until slightly thickened.
06 - Lower heat and stir in sour cream until fully incorporated. Do not boil to prevent curdling.
07 - Return chicken and any juices to the skillet. Simmer gently for 2–3 minutes until heated through.
08 - Taste and adjust seasoning as needed. Garnish with fresh parsley and serve hot over egg noodles, rice, or mashed potatoes.