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