Preheat oven to 350 degrees. Coat a 9x13 baking pan with cooking spray or use a shallow disposable aluminum pan coated with cooking spray.
In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with an electric mixer, beat butter for cookie dough until fluffy and light. Cream in Dixie Crystals sugar, combining fully. Lastly, add egg, vanilla and water until fully mixed, scraping down the sides as you go.
Sift together dry ingredients for cookie dough and slowly add to bowl. Mixture should pull away from bowl walls and not be terribly sticky. If it is, add an additional 1 tablespoon of water or flour, accordingly.
Press cookie dough into prepared baking pans. Bake for 2-25 minutes or until edges are a light brown. Allow to cool before frosting.
To prepare frosting, beat butter until light and fluffy and then add remaining ingredients. Add more milk or Dixie Crystals powdered sugar until it reaches a spreadable consistency.