Preheat the oven to 425°F. Line a 4-inch-deep roasting pan with parchment paper.
Pat the chicken very dry with paper towels. Using sharp kitchen shears or a sharp knife, cut along one side of the backbone, leaving the other side attached.
Lay the chicken breast-side up on a cutting board and press down on the breastbone with your hands to flatten the chicken. Liberally season the chicken all over with the rosemary and salt and pepper.
Transfer the chicken breast-side up to the pre- pared roasting pan.
Roast on the bottom rack of the oven for 40 to 45 minutes, until the thickest part of the thigh registers 165°F on an instant-read ther- mometer. Use a turkey baster or large spoon to baste the chicken with the juices from the pan.
Set the oven to broil, but keep the chicken on the bottom rack (putting the parchment paper closer to the broiler could cause it to catch fire). Broil for four to five minutes, until the skin is golden brown and crispy.
Transfer the chicken to a grooved cutting board to catch any juices and let it rest for five to ten minutes before carving and serving.
Watch Your MorningDaily at 6am ET on CTV and CTV News Channel