A cracker is a type of biscuit that developed from military hardtack and nautical ship biscuits. The holes in crackers are called "docking" holes. The holes are placed in the dough to stop air pockets from forming in the cracker while baking. In U.S. English, the name "cracker" is most often applied to flat biscuits with a savory, salty flavor, in distinction from a "cookie," which may be similar to a "cracker" in appearance and texture, but has a sweet flavor. Crackers may be further distinguished from cookies by the manner in which they are made. Crackers are made by layering dough and cookies are made in any manner a cake would be made. Crackers sometimes have cheese or spices as ingredients, or even chicken stock. Some crackers are salted flour products. Brands including Captain's Wafers, Club Crackers, Town House Crackers, Ritz Crackers, Cream crackers and Water biscuits are used spread with cheese, pÃ¢tÃ©, or mousse. Saltine and oyster crackers are often used in or served with soup. Mock apple pie is made from Ritz (or similar) crackers. Animal crackers are the subject of debate as to whether they are cookies, or crackers. One side states that they are a cracker, an exception to the rule-of-thumb "crackers are salty/savory; cookies are sweet." Plus, the manner in which animal crackers are made (layered dough) classifies them as crackers. However, the sweet taste and texture of the dough would lead the other side to believe that they are, in fact, cookies. Graham crackers and digestive biscuits are also eaten as cookies, although they were both invented for their supposed health benefits. A popular snack is crackers with cheese as a topping.