01 - Season the chicken strips evenly 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 and cooked through, approximately 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 constantly to coat evenly. Cook for 1 minute to remove raw flour taste.
05 - Gradually whisk in chicken broth while stirring. Add Dijon mustard, paprika, and Worcestershire sauce. Simmer for 3–4 minutes until slightly thickened.
06 - Reduce heat to low. Stir in sour cream until fully incorporated—do not boil to prevent curdling. Return chicken and accumulated juices to the skillet. Simmer gently for 2–3 minutes until heated through.
07 - Taste and adjust seasoning as needed. Garnish with fresh parsley and serve hot over egg noodles, rice, or mashed potatoes.