Sugar Cookies - THE BEST

1 cup butter, softened
2 cups sugar
2 eggs
3 teaspoons vanilla
1 cup sour cream
1 teaspoon salt
2 teaspoons baking soda
5 1/2 cups flour
Frosting
1/2 cup butter, softened
4 cups powdered sugar
2 teaspoons vanilla
1/4 cup milk, add more milk if needed

Preheat oven to 375 degrees. In a mixer cream
butter and sugar; add eggs and vanilla, mix well.
Combine salt, soda and flour. Add to mixer 1/2
sour cream than 1/2 of the flour mixture, repeat;
mix well after each addition. Roll out dough to 1/4
to 1/3 of an inch, not any thicker. Cut out cookies
and bake for 7-8 minutes. They should be pillow-like
but not brown.

For frosting cream butter, sugar an vanilla.
Gradually add milk.