A Yule log is a traditional Christmas food, often served in France, Belgium, and Switzerland as well as various former French colonies such as Canada. It's typically made of sponge cake and decorated to resemble a real Yule log.

Tagging: As of the time of this wiki entry's creation, the only Yule logs on e621 are the cakes. For the original Yule log that is little more than a log tossed on a fire during the Christmas season, tag log + Christmas.

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Yule log (cake) (Wikipedia))