For the cookies:
Preheat oven to 350° F.
Line baking trays with parchment paper and set aside. In a bowl, briefly mix together the flour, salt, baking soda and spices with a whisk and set aside. In a bowl with a hand mixer or in the bowl of a standing mixer fitted with the flat beater, cream the butter and brown sugar.
Add the egg, vanilla and molasses and blend well, scraping down the sides of the bowl as needed.
Add the dry mixture and the buttermilk alternatively to blend well.
Drop by teaspoonfuls on the baking trays, about 2 inches apart. Bake for 9 to 11 minutes or until the cake bounces back when pressed. Keep unused dough in the refrigerator while baking trays. Let cool completely.
For the frosting:
Unwrap candy canes or candies and place in a zip-top bag. Over a cutting board or dish towel, crush the candy with a mallet, rolling pin or hammer. Set aside.
With a hand mixer or in a standing mixer fitted with a wire whip, blend together the butter, cream cheese, confectioner's sugar and vanilla extract.