Speculaas cookies, also known as windmill cookies are a delicious crunchy cookie that is full of flavor, thanks to the special speculaas spice mix. Speculaas is highly connected with St. Nicolas Day in Holland but luckily nowadays its available year round. Speculaas or speculoos? Though the names are very similar the cookies themselves are not. In the early 20th century, speculoos was developed by the Belgians as they had access to very inexpensive spices. 'Loos' in Dutch means without, so the name literally means without spices.