For the cookie dough, cream together sugar, butter, and shortening. Add egg, buttermilk and vanilla, mixing well to combine. Add flour, baking powder, baking soda and salt, mixing well until soft dough forms. Place dough in a plastic bag, flatten and freeze for 30 minutes. In a small bowl, mix together cinnamon and sugar. Set aside. When dough is firm, combine 2 tablespoons of flour and 2 tablespoons of powdered sugar. Generously flour a work surface. (If you don’t have powdered sugar, just use flour.) Working quickly, remove dough from bag and roll out into a 12X 9 rectangle about 1/4-inch thick with a floured rolling pin. Brush the surface of dough with melted butter. Sprinkle brown sugar cinnamon mixture over dough and press down slightly. Flour your hands and then quickly roll dough lengthwise into a tight log. Wrap log up in plastic wrap; twist the edges to seal and place on a tray. Freeze for 30 minutes or until the roll is firm enough to cut into pinwheel slices ½ inch thick. Place cookies on parchment paper or silicone mat about 2-inches apart. Return to fridge for 15 minutes. Bake for 10 minutes. Cookies should be slightly underdone. While cookies are baking, make the cream cheese frosting or the sugar glaze. For the cream cheese frosting, combine cream cheese, butter, powdered sugar, vanilla and milk. For the glaze, mix together powdered sugar and milk until desired consistency is achieved. When cookies are done and still warm, spread either the cream cheese frosting over cookies or drizzle with glaze. Place cookies in an airtight container to store.
*To make homemade buttermilk, combine 1/3 cup milk and 1 tablespoon vinegar or lemon juice. Stir for 10 seconds then let sit for 15 minutes.