Remove chicken from refrigerator 30 minutes before cooking to bring to room temperature.
Preheat oven to 425°F (220°C). Position rack in lower third.
Arrange chopped carrots, celery, and onion in the center of a roasting pan to create a natural rack.
Pat the chicken completely dry inside and out with paper towels. This is crucial for crispy skin.
Season the cavity with ½ tablespoon salt, ½ tablespoon pepper, half the fresh herbs, and one lemon half.
Make herb butter: Combine softened butter with minced garlic, 1 teaspoon salt, ½ teaspoon pepper, and 1 tablespoon chopped herbs.
Loosen the skin over the breast and massage ⅔ of the herb butter under the skin. Rub remaining butter over the exterior.
Drizzle with olive oil, then sprinkle with remaining salt, pepper, and paprika. Squeeze remaining lemon half over the bird.
Truss the chicken with kitchen twine (or tuck wings under).
Place chicken breast-side up on the bed of vegetables.
Roast at 425°F for 15 minutes, then reduce temperature to 375°F (190°C).
Continue roasting for approximately 1 hour to 1 hour 15 minutes, until an instant-read thermometer inserted into the thigh reads 165°F (74°C).
Rest the chicken on a cutting board, tented with foil, for 15-20 minutes before carving.
Carve and serve with roasted vegetables and pan juices.