Preheat the oven to 450°
Place all cut vegetables in the bottom of Good Cook 9x13 Ceramic Baker. Combine the salt, pepper, thyme, and zest of the lemon in a small bowl, sprinkle 1 teaspoon of the seasoning over the cut vegetables in the bottom of the pan. Season the chicken inside and out with the salt mix, including between the skin and meat, using all but 1 teaspoon of the seasoning. Stuff 1 lemon half and thyme stems inside the bird.
When the oven is hot, remove the skillet and add the oil followed by the cauliflower and sprinkle with the remaining seasoning mix, and then immediately place the chicken, breast side down on top of the vegetables. Roast, undisturbed, for 35 minutes, and then flip the bird breast side up to crisp. Cook the pan for 15 minutes more, or until an instant-read thermometer inserted in the meaty part of the thigh registers 155°, or juices run clear. Remove from the oven and let rest, uncovered (to stay crispy) for 5 minutes, as the temperature of the chicken will climb 5 degrees and the juices will settle a bit. Using tongs, squeeze lemon over chicken and discard thyme stems.