Preheat your oven to 425°F.
In a large bowl, combine the potatoes, carrots, radishes, garlic, lemon zest, and lemon juice. Toss them well to coat with the juices and flavors.
Add the lemon slices, rosemary, and parsley to the bowl. Mix everything together until the vegetables are well coated.
Drizzle the olive oil over the mixture, ensuring all the vegetables are evenly covered.
Season your mixture generously with salt and ground black pepper to taste.
Pour the seasoned vegetables into a 9×13-inch baking pan, spreading them out into a single layer.
Cover the pan with foil and bake for approximately 30 minutes.
Meanwhile, prepare the chicken leg quarters. If desired, gently spread softened butter under the skin of the chicken for extra richness.
After 30 minutes, remove the vegetables from the oven and take off the foil. Place the seasoned chicken skin side up over the roasted vegetables.
Return the pan to the oven and roast uncovered at 425°F for approximately 30 minutes, or until the chicken is done.