I'm originally from Minnesota and have lived in Colorado for many years.  My gram made the best sugar cookies in MN and I have tried to modify the recipe to work here, but no success.  Could anyone help me please?  1/2 cup butter, 1/2 cup shortening, 1 cup sugar, 1 egg, 2 1/4 cups of unsifted flour, t tsp cream of tartar, 1 tsp baking soda and 1 tsp vanilla.  Bake 375 degrees for 9 minutes  thanks