In American Cookery, published in 1796, we start to see the use of pearlash. Pearlash is potassium carbonate, an alkaline from wood ash. Today we use bicarbonate soda, baking powder or self-raising flour, but the use of pearlash allowed for a more cake-like consistency, rather than a cookie. It’s possible the change in density drove the name change between cakes and cookies.

At some point in history, cakes (whether tea cakes or sweet cakes) began being called cookies or biscuits, depending on the country. At the time of The Legend of Sleepy Hollow, it’s possible there was a transition happening. The first American cookbook American Cookery by Amelia Simmons (published in 1796) gave cookies (or cookey in some cases) their own category in a cookbook. However, it’s possible that using the word ‘cakes’ took a while to transition to the word cookie.