Speculaas are spiced cookies mainly made in Belgium and the Netherlands, although they are also popular in Germany (Rhineland and Westphalia), Luxembourg and northern France. With an intense fragrance of cinnamon, cloves, nutmeg, and ginger, the cookies are traditionally baked on the eve of St Nicholas Day, celebrated on December 5 and December 6.
Before going to bed, the children put their shoes by the chimney, and if they behaved well, they are rewarded with speculaas in their shoes. There are a few theories on the origin of its name - one says it derives from the Latin word speculum, meaning a mirror, referring to the mirrored images that the cookies are decorated with.
And how about the issue of speculaas vs. speculoos? Apparently, speculoos is just the Belgian word for these cookies, but without any (or most of) the once-expensive spices, as loos means without in Dutch. Also, the word speculaas doesn't exist in French, so they're always called speculoos in France.