Move oven rack to middle position and preheat to 375℉.
Remove any of the innards stashed in the cavity of the bird reserving neck. Pat the chicken dry with a paper towel.
Rub the chicken thoroughly with 1½ tablespoons olive oil, 2 tablespoons salt, and 1 teaspoon of pepper.
Stuff the cavity with ½ lemon and some of the herbs.
Slice the sweetpotato into ¾ inch rounds. Toss the rounds in additional olive and salt.
In a cast iron skillet, arrange the sweetpotato rounds so that the bottom of the skillet is covered. Note: Do not overlap sweetpotatoes.
Lay the additional herbs on top of the potatoes.
Truss the chicken. Note: Tying wings and legs close to the body allows for better browning and chicken with a crispy skin.
Position the chicken breast side up on top of the sweetpotato rounds.
Place in oven. Roast for 1 hour.
Before serving, squeeze the remaining half lemon over top.