Preheat oven to 375 degrees F (190 degrees C). Sift together flour, baking soda, salt, ginger, and cinnamon; set aside.
Cream butter, and gradually blend in sugar until light and fluffy. Beat in egg and molasses. Mix in sour cream alternately with sifted dry ingredients. Drop dough by teaspoonfuls onto ungreased cookie sheets.
Bake 10 to 12 minutes in preheated oven. Transfer to wire racks to cool.