Roughly chop all veggies into equal-sized pieces and place in the bottom of baking pan or cast-iron skillet.
Drizzle with avocado or olive oil and season with 1 tbsp Italian seasoning and a pinch of salt and pepper.
Preheat oven to 425.
Remove chicken from packaging and pat dry with a paper towel. Remove the neck part and gizzards.
Flip the chicken over so that it is breast-side down. Using strong kitchen shears or poultry shears, cut on either side of the backbone to remove it, from the tail to the neck. Do one side at a time. It shouldn’t be very difficult to cut through the skin/bones if you are in the right spot.
Flip the chicken back over so that it is breast side up and continue to pat dry with a paper towel if needed. Press down on the breastplate until you hear a “crack” and the chicken lays flat.
Coat the chicken with 2 tbsp melted butter or oil.
Season the chicken with 3 tbsp poultry seasoning, or use an Italian or Tuscan seasoning that you have on hand.
Place the chicken either directly on top of the veggies or on a baking rack in the baking pan.
Roast the chicken until the internal temperature of the thickest part of the breast is 145 degrees.
Rest for 20-30 minutes before carving.