Prepare Oven and Pan: Preheat the oven to 375°F (190°C). In a large 9x13 inch baking dish or roasting pan, spread the potato wedges and sliced onions in a single layer. Drizzle with a small amount of the olive oil (about 1 tbsp) and sprinkle with 1/2 teaspoon of the kosher salt and half the black pepper.
Prepare Chicken: Pat the chicken pieces thoroughly dry with paper towels. Loosen the skin and rub the remaining 1/2 teaspoon of kosher salt directly onto the meat underneath. Arrange the chicken pieces, skin-side up, amongst the potatoes and onions.
Mix the Sauce: In a small bowl, combine the minced garlic and the remaining extra virgin olive oil. Let it stand for 5 minutes to infuse. Whisk in the lemon juice, dried thyme, smoked paprika, and remaining black pepper.
Assemble the Dish: Pour the lemon-herb sauce evenly over the chicken and potatoes. Arrange the lemon slices over the top of the dish. Carefully pour the low-sodium chicken broth into the side of the pan, avoiding washing the sauce off the chicken.
Roast: Bake uncovered for 45 to 55 minutes, or until the chicken is cooked through (internal temperature reaches 165°F) and the potatoes are tender.
Finishing Touches: If you desire darker, crispier skin on the chicken, move the oven rack closer to the top and turn on the broiler. Broil for 2 to 4 minutes, watching very carefully to prevent burning. Remove the pan from the oven and scatter the Kalamata olives (if using) and fresh parsley over the top.
Serve: Let the dish rest for 5 minutes before serving warm.