Sour Cream Sugar Cookies

½ cup butter, softened
1 cup sugar
1 egg
1 teaspoon vanilla
1 cup sour cream (don't use light or fat free)
3 ¼ cups flour
1 teaspoon baking soda
½ teaspoon salt

In a mixing bowl cream together the butter and sugar. Add the egg, vanilla and sour cream.  Mix until well combined. Mix in the dry ingredients. Refrigerate the dough overnight. Roll out thin and cut with cookie cutters. Bake at 350 degrees for 11 minutes.