Soft Sour Cream Sugar Cookies

This is the recipe that my mom always uses.  It's great, and the cookies are really soft.  

Soft Sugar Cookies

2 c. sugar

2/3 c. butter

3 eggs

1 tsp. vanilla

1 cup sour cream

5 cups flour

1 tsp. baking soda

2 tsp. baking powder

1 1/2 tsp. salt

Mix ingredients in the order above.  Chill dough at least an hour.  Roll out on floured surface.  Bake at 400 degrees 5-7 minutes.