The King Cake is celebrating Epiphany.
It's a flaky cake filled with Frangipane (or almond cream). A figurine, la fève, is hidden in the cake and the person who finds the trinket in their slice becomes king for the day and will have to offer the next cake!
It is traditional for the youngest person to place themselves under the table and name the recipient of the share which is indicated by the person in charge of the service.
The cake stays fresh for 2 days after pick-up or delivery. It is usually served warm.