Preheat your oven to 180°C (350°F). Prepare your roasting pan and set aside.
Mix chopped thyme, rosemary, lemon zest, salt, and pepper, then rub this herb mixture all over the chicken, including under the skin if possible.
Place the seasoned chicken in the roasting pan, breast side up, and insert a meat thermometer into the thickest part of the thigh.
Put the chicken in the oven and roast for about 1 hour and 30 minutes, basting occasionally with pan juices, until the internal temperature reaches 75°C (165°F) and the skin is golden brown.
While the chicken roasts, toss carrots, parsnips, and sweet potatoes with melted butter, salt, and pepper, then spread them on a baking sheet.
Roast the vegetables in the oven alongside the chicken for about 40-45 minutes, until they are tender and caramelized around the edges.
Meanwhile, prepare the cranberry sauce by combining cranberries, sugar, and ½ cup of water in a saucepan. Bring it to a boil over medium heat, then simmer until the cranberries burst and the sauce thickens, about 10 minutes.
Once the chicken reaches the correct internal temperature, remove it from the oven, tent loosely with foil, and let it rest for 15 minutes to retain its juices.
Carve the chicken into slices, arranging it on a serving platter.
Serve the carved chicken with a side of roasted root vegetables and a spoonful of tart cranberry sauce for a colorful, festive presentation.