Place the chicken and potatoes in an oven-proof casserole.
Drizzle with olive oil and lemon juice.
Sprinkle with rosemary, garlic, scallions, salt, and pepper.
Marinate in the refrigerator for 30 to 60 minutes, turning occasionally.
Bake covered in a preheated 400F (200C) oven for 30 minutes.
Add the olives and mushrooms and bake an additional 30 minutes.
Calories: 75kcal | Carbohydrates: 6g | Protein: 2g | Fat: 5g | Saturated Fat: 1g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Sodium: 291mg | Potassium: 100mg | Fiber: 3g | Sugar: 1g