My faaaaavorite recipe for the classic sugar cookies. They don’t rise at all so they don’t get that weird puffy look. Don’t use their recipe for icing, though. Who uses powdered egg whites anyways? Nah, 2 cups powdered sugar, 1 tsp. light corn syrup and 1 tsp. milk (give or take the measurements to the consistency you want), plus food coloring, is all you need.
Though I do agree with them, gel food coloring is the best for bold colors. If you don’t have piping bags, plain old ziploc bags with a teeny tiny hole cut in a corner works just as well.