Sugar Cookies

got this from Andrea and everyone says how good they are!
combine:
1 cup sour cream
2 1/4 cup sugar
1 cup shortening
4 eggs
1 tsp vanilla
Mix well
combine:
6 cups flour (reserve 1 cup)
3 tsp baking powder
1 tsp baking soda
1 tsp salt
Add to wet ingredients-add flour mixture slowly until all mixed. ( I usually have to add at least another cup of flour)
Chill dough at least 15 min
Roll out on floured surface- may need to add more flour?
Bake @ 350 for NO MORE than 10 min