Preheat + prep the pan: Preheat the oven to 400°F (204ºC). Lightly spray a 9×13 baking dish with cooking spray. (For crispier skin, place a wire rack inside the dish or arrange sliced onions under the chicken to lift it slightly.)
Dry the chicken: Pat the chicken leg quarters(4) very dry with paper towels and set aside.
Mix the seasoning: In a small bowl, combine the olive oil (2 tablespoons), smoked paprika (1 teaspoon), garlic powder (1 teaspoon), onion powder (1 teaspoon), salt (1 1/2 teaspoons), pepper (3/4 teaspoon), and optional brown sugar (1/2 teaspoon) or dried herbs (1/2 teaspoon) if using. Rub the seasoning mixture all over the chicken, coating both sides evenly and working it into the skin.
Season the chicken: Arrange the chicken skin-side up in the prepared baking dish, leaving space between each piece so the skin roasts instead of steaming.
Arrange for crisp skin: Bake uncovered for 55–65 minutes, or until the skin is golden and crisp and the internal temperature reaches 175°F (79ºC) in the thickest part of the leg.
Bake until tender: While the chicken bakes, melt the butter 91/4 cup) in a small saucepan over low heat. Add the garlic (2 cloves) and parsley (1 tablespoon) and cook for 30–60 seconds, just until fragrant. Remove from heat and stir in lemon juice if using.
Make the garlic butter: Once the chicken is done, spoon or brush the garlic butter over each piece. Let the chicken rest for 5–10 minutes to keep it juicy. Spoon the pan drippings over the chicken just before serving.
Finish + rest: Spoon or brush the garlic butter over each piece of chicken. Let the chicken rest for 5–10 minutes to keep it juicy.
Serve with drippings: Spoon the pan drippings over the chicken just before serving.