1. Beat shortening and sugar until well mixed. Add eggs and beat until light and fluffy. Add sour cream and vanilla. Mix well. 2. Add baking soda, baking powder and salt. Add flour, 1 cup at a time until the mixture is very thick. 3. Cover dough and chill in the refrigerator for several hours. 4. Roll out on floured surface to desired thickness and cut with cookie cutters. If desired, you may dust the tops with granulated sugar, before baking. 5. Bake at 350 degrees for 8-10 minutes, depending on the thickness of the dough. Cookies should just be lightly browned and soft when taken from the oven. Cool on wire rack and frost.