Sugar cookies and snickerdoodles may seem similar if you read the list of ingredients: sugar, butter, etc. However there are a few things that set the cookies apart.  Snickerdoodles use cream of tartar while sugar cookies use baking powder.  Snickerdoodles have cinnamon in the dough and they are rolled in cinnamon sugar.  Sugar cookies are made with only butter, while snickerdoodles use a mixture of butter and shortening!