Pat dry the chicken with paper towel. Sprinkle salt and pepper all over the chicken, include its cavity and the back.
Transfer the chicken to a roasting pan, tuck the wing tips behind the shoulders.
Cover with plastic wrap and let the chicken marinade for at least 1 day (maximum 2 days) in the fridge.
When ready to cook, take the chicken out and leave it at room temperature for 10-15 minutes
Pre-heat oven to 450F
Pat dry the chicken with a clean paper towel. Leave 1-2 sprigs of fresh thyme inside its cavity.
Add the remaining thyme, carrots and onions in a roasting pan or a cast-iron skillet. Put the chicken, breast side up on top of the vegetables.
Place the chicken on the center rack of the oven and roast for 30 minutes.
After 30 minutes, raise temperature of the oven to 460F. Take the chicken out and use two spatulas to carefully flip it over.
Return the chicken to the oven and roast for another 15 minutes.
After 15 minutes, take the chicken out again and flip it back. Return the chicken to the oven and continue cooking for another 5-10 minutes. The breast should turn into golden brown or deep brown color.
Take the chicken out of the oven and let it rest for 10 minutes then transfer it to a serving platter.
Serve chicken immediately with the roasted roasted carrots & onions. Pour the drippings over the chicken right before you're ready to serve.
