First, preheat the oven to 450 degrees.
Second, peel the carrots, cut them into halves, cut them again lengthwise, and place them into the baking dish.
Next, chop the onion in half, cut each half into pieces, and place them into the baking dish.
Chop the red potatoes in half, cut each half into pieces, and place them into the baking dish.
Pour the avocado oil and seasonings onto the vegetables and mix well with your hands until all of the vegetables are coated evenly and set aside.
Take the whole chicken and place it onto a cutting board.
Next, take some paper towels and pat the chicken completely dry.
Then, take the 6 tablespoons of softened butter, add the seasonings, and mix well.
To season the chicken, pull the skin up and slide your hand between the meat of the chicken and the skin. The skin will detach from the flesh and you will be able to rub the herb better into the meat. Do this until you've used most of the herb butter and until the chicken is coated completely underneath the skin on both sides.
Next, take the remaining butter and rub it onto the outside of the chicken on all sides.
Then, take the lemon and put the two halves into the cavity of the chicken.
Sprinkle the outside of the chicken with one final teaspoon of Tony's Chachere's Cajun Seasoning.
Place the chicken, breast side up, on top of the seasoned vegetables and tuck the wings underneath.
Bake the chicken at 450 degrees for 15 minutes and then lower the oven temperature to 375 and roast for an additional hour or until the internal temperature of the chicken reaches 165 degrees. (This will depend on the size/lb. of your chicken)
Finally, once your chicken has reached 165 degrees internally, remove it from the oven and let it rest for 20 minutes for the juices to redistribute before carving.
Serve over rice with the pan drippings drizzled over the chicken and enjoy!