Preheat the oven to 450 degrees F.
Rinse the chicken inside and out and pat dry. Generously sprinkle salt and pepper inside the cavity, and then add the rosemary, thyme, onion, garlic and lemon. Once the herbs are inside the cavity, truss the chicken.
Place the chicken in a roasting pan and rub olive oil over the skin. Sprinkle with salt and pepper, and then place in the oven for 15 minutes.
After 15 minutes, take the chicken out and add the potatoes, shallots and carrots to the pan. Roast until the juices run clear, another 45 minutes. Remove from the oven and let rest on a carving board for about 10 minutes.
While the chicken is resting, remove the vegetables from the pan and drain most of the chicken fat. On medium heat, add the escarole to the pan and saute until wilted halfway. Combine the Dijon mustard, vegetables and escarole into a serving dish. Carve the chicken, place on top and serve.