Here, big pieces of freshly cracked black pepper, charred lemon, and sweet fennel lend big flavor to an otherwise humble dish.
Preheat oven to 400 degrees F.
Place carrots, onions, celery, and diced fennel in a roasting pan or skillet, season with olive oil, salt, and pepper; set aside.
Rinse the chicken, pat dry, and place on a cutting board. If desired, remove wishbone and manchonner the wing tips and legs.
Generously season the inside of the chicken cavity with salt and pepper. Next, stuff the cavity with thickly sliced fennel, halved garlic, lemon quarters, fennel stems, and half of the fresh thyme sprigs. Truss the chicken tightly.
Place chicken on the bed of vegetables and drizzle with melted butter. Generously season with salt and cracked pepper and rub the chicken to ensure it is evenly coated with seasoning.
Arrange the remaining lemon and thyme around the chicken and roast in the oven for 50 minutes to 1 hour 15 minutes or until an internal temperate reaches 165 degrees Fahrenheit.
Rest for 15 minutes before slicing. Before serving, squeeze the charred lemon over the roasted, caramelized vegetables.