Marinate Chicken: Combine garlic, lemon juice, oregano, paprika, olive oil, salt, and pepper. Coat chicken and refrigerate for 1+ hours.
Roast Potatoes: Toss potatoes with oil, garlic powder, rosemary, and salt. Roast at 400°F (200°C) for 25 minutes.
Cook Chicken: Sear chicken skin-side down in a skillet for 5 minutes. Flip, then transfer to the oven with potatoes for 20-25 minutes.
Make Pesto: Sauté mushrooms until golden. Blend with basil, pine nuts, Parmesan, cream, oil, garlic, salt, and pepper until smooth.
Serve: Plate chicken and potatoes, drizzle with pesto, and top with feta and parsley.