Preheat oven to 425ºF with the oven rack in the lower third.
Remove the gizzards from the chicken, rinse the inside and outside under water, and pat dry until it is completely dry. Any moisture will create steam and the skin won't get crispy. Leave on a cutting board at room temperature while you prepare the vegetables.
In your cast iron skillet (or roasting pan or glass baking dish), place the vegetables in an even layer. Drizzle with 2 teaspoons olive oil, salt and pepper.
Stuff the inside of the chicken with the lemon, onion, garlic and fresh herbs. Season the chicken with 1 tablespoon salt and pepper. Place the chicken in the middle of the cast iron skillet on top of the vegetables.
Roast for 60-90 minutes, until the skin is golden and crispy and the thickest part of the breast has in internal temperature of 165ºF using a meat thermometer. Mine usually takes about 70 minutes.
Remove the from oven. Lift the chicken out, tilt the chicken so all the internal juices drip on top of the vegetables. Put the chicken on a cutting board to rest for 10 minutes uncovered. (If you cover it, it creates steam and the chicken skin will get soggy!) Toss the vegetables in all the chicken juices, and return to the oven for another 20 minutes to caramelize.