Spatchcocked Chicken with Potatoes

Preheat oven to 500 degrees. Season chicken with salt and ground pepper. Using your fingers, loosen skin from breast meat; tuck lemon slices and 2 springs thyme between skin and meat. Place chicken, breast side up, in a pan. In a bowl, toss potatoes, onion wedges, and 2 sprigs thyme with olive oil; season with salt and pepper. Add to pan.

Roast chicken until juices run clear when pierced between breast and leg (an instant-read thermometer should read 165 degrees when inserted in thickest part of a thigh, avoiding bone), about 30 minutes. Let rest 5 minutes before carving.