In a large bowl mix the dry ingredients. With your fingers or two knives, mix in the shortening or butter until it resembles coarse meal. Add the buttermilk, mixing in a little at a time until it forms a sticky dough, Turn the dough out on a lightly floured surface and knead a few times, adding more flour as needed until the dough is smooth and no longer sticky.With a floured rolling pin roll into a 1/2 inch thickness. In a small bowl mix the sugar and cinnamon. Brush the dough with the butter and evenly spread the cinnamon sugar on top. Cut out the biscuits, using a round or square 2 inches cutter. Place on a lightly greased cookie sheet and bake for 12 minutes or until golden and puffed.