Learn how to make the ultimate roast chicken with lemons and onions. After you master our definitive roast chicken recipe, check out our step-by-step guide to carving your bird.
Add coriander, cumin, or paprika to the salt, if desired. Pat chicken dry and season the cavity and skin with 1 1/2 teaspoons salt each. Place it on a rimmed baking sheet lined with a rack. Refrigerate, uncovered, at least 12 hours and up to 24 hours.
Sprinkle the cavity with 1/4 teaspoon pepper. Then pierce whole lemon all over with a fork; put it inside the cavity with 6 thyme sprigs. Rub butter evenly over the skin, season with another 1/4 teaspoon pepper, and tie the legs firmly with twine. On a rimmed baking sheet lined with parchment, overlap lemon and onion slices to create a base slightly larger than the chicken. Set the bird on top of this "rack," which will collect the chicken fat as it drips. Strip the leaves from remaining 3 thyme sprigs and scatter them over the chicken. Let the bird stand at room temperature for 30 minutes, which will help it cook evenly.
Preheat the oven to 450 degrees. Roast the chicken 20 minutes, then reduce the heat to 350 degrees, rotate the sheet, and continue cooking until a thermometer registers 160 degrees, 25 to 35 minutes. (For the most accurate reading, insert it in two places: the thickest part of the breast, then the thigh, near but not touching the bone.) Let the chicken stand 10 minutes (the temperature will rise to 165 degrees) -- this allows the juices to redistribute, creating tender meat. Serve, with the roasted lemon and onion slices.