In gastronomy, a wafer is a crisp, often sweet, very thin, flat, and dry biscuit, often used to decorate ice cream.Wafers can also be made into cookies with cream flavoring sandwiched between them.They frequently have a waffle surface pattern but may also be patterned with insignia of the food's manufacturer or may be patternless. Many chocolate bars, such as Kit Kat and Coffee Crisp, have wafers in them.afers can also be made into cookies with cream flavoring sandwiched between them. They frequently have a waffle surface pattern but may also be patterned with insignia of the food's manufacturer or may be patternless. Many chocolate bars, such as Kit Kat and Coffee Crisp, have wafers in them.