Polka Dot Bake Shop, 1730 E. Woodlawn Road, has introduced a savory item: CrispiThins gour met crackers. CrispiThins are the first cracker made with sweet potatoes and are available in four flavors: Original, Cracked Black Pepper, Rosemary and Smoked Chipotle. CrispiThins made their debut at the Summer Fancy Food Show in New York City in late June. A four pack of all flavors is $23 and can be shipped. Individual packages are available as well.