Whisk together the flour, baking soda, baking powder, cinnamon and salt in a large bowl. In your mixing bowl, cream the butter (or shortening), sugar and molasses together using your stand or hand mixer on medium speed. Add the eggs one at a time and mix in completely. Add the dry ingredients in thirds, alternating with the buttermilk. The mixture is going to end up thick, almost like cookie dough. Once the cake batter is mixed together, cover the bowl and refrigerate for at least an hour.