Heat olive oil and 1 tbsp butter in a large skillet over medium heat. Sear chicken until golden, then set aside.

Add remaining butter to the pan, sauté onions until translucent, then add garlic and paprika. Stir for 1 minute.

Add mushrooms and cook until softened and golden.

Pour in chicken broth, bring to a simmer, and return chicken to the pan. Cook for 5 minutes.

Reduce heat, stir in sour cream and mustard. Simmer gently, ensuring not to boil. Season with salt and pepper.

Serve over pasta or rice, garnished with parsley.