Sprinkle seasonings over both sides of chicken. Place chicken, veggies and water in an electric turkey roaster or baking dish, cook covered on 375 for about 1 to 1-1/2 hrs. till food thermometer reaches 180. Time will vary depending on size of chicken breast.
Peel, cube and boil potatoes, when fork goes through easily, drain, add butter and a little room temp ff milk, salt & pepper. Smash, add more milk if necessary to reach consistency desired.
For the gravy, I thaw and use ckn stock I have previously frozen (I put current broth in fridge overnight, skim off fat and freeze). Heat broth in skillet or med. size saucepan, mix water or milk and cornstarch, add to broth and simmer till thickened, at salt & pepper to taste.