Old-fashioned, soft sugar cookies

This is by far one of my favorite cookie recipes ever. It used to sound so strange to me that there is sour cream in it, but I quickly overcame that!

1/2 C butter
2 Eggs
3 C flour
1/2 tsp baking powder
1/2 tsp baking soda
1 1/2 C sugar
1 tsp vanilla
1 tsp salt
1 C sour cream
sugar-cinnamon mixture

Cream butter to the consistency of mayonnaise. Add sugar gradually while continuing to cream. Add eggs. Add vanilla, salt, baking powder, and baking soda. Add flour alternately with sour cream. Drop by teaspoons onto a greased cookie sheet. Sprinkle with sugar-cinnamon mixture. Bake at 375 degrees for 10-12 minutes. While hot, sprinkle again with sugar-cinnamon mixture.