Preheat and prep. Heat your oven to 425°F (220°C).
Lightly oil a large baking dish or sheet pan for easy cleanup.
Season the potatoes. In a bowl, toss the potato chunks and onion wedges with 2 tablespoons olive oil, half the minced garlic, half the oregano, half the paprika, half the salt, and a few grinds of pepper. Spread them in an even layer in the baking dish. Drizzle in the chicken stock or water.
Pat the chicken dry. Use paper towels to remove surface moisture from the chicken skin.
Dry skin means better browning and crispiness.
Make a quick rub. In a small bowl, mix the remaining 1 tablespoon olive oil with the rest of the garlic, oregano, paprika, salt, pepper, garlic powder, and chili flakes if using. Add the juice of half the lemon.
Season the chicken. Rub the mixture all over the chicken, getting some under the skin if possible. Place the chicken pieces skin-side up on top of the potatoes.
Tuck a few lemon slices around the pan.
Roast until golden. Bake for 35–45 minutes, depending on the size of the pieces. The chicken is done when the skin is crisp and the internal temperature hits 165°F (74°C). The potatoes should be tender and browned at the edges.
Broil for extra crisp. If the skin needs more color, broil on high for 2–3 minutes, watching closely so it doesn’t burn.
Rest and finish. Let the chicken rest for 5–10 minutes.
Toss the potatoes with any juices in the pan. Taste and adjust salt. Sprinkle with chopped parsley or thyme.
Serve with the extra lemon wedges.