A snickerdoodle is a type of sugar cookie made with cream of tartar and rolled in cinnamon sugar. It is characterized by a cracked surface and can be crisp or soft depending on preference. In modern recipes, the leavening agent is usually baking powder.
Some people mistakenly refer to snickerdoodles as "sugar cookies". The difference between the two comes from the use of cinnamon, which is balanced with cream of tartar to give the cookies their sweet, spicy flavor.
The Joy of Cooking claims that snickerdoodles are probably German in origin, and that the name is a corruption of the German word Schneckennudeln, which means "snail dumpling." A different author suggests that the word "snicker" comes from the Dutch word snekrad, or the German word Schnecke, which both describe a snail-like shape. Yet another theory suggests that the name comes from a New England tradition of fanciful, whimsical cookie names. There is also a series of tall tales about a hero named "Snickerdoodle" from the early 1900s which may be related to the name of the cookie.