butter, room temperature
Measure flour, salt, baking powder and soda. Cream butter with sugar. Beat in eggs and vanilla. Sift in flour mixture; adding alternately with sour cream and blending well to make a think batter.
Drop by medium tablespoonfuls 4" apart, on greased cookie sheet. Spread into 2" rounds. Sprinkle with cinnamon sugar.
Bake in 400 degree oven for 12 minutes or until likely golden around edges. Cool completely on wire racks.