During the Christmas season, Portuguese pastry stores transform many tons of flour, sugar, eggs, port wine, and candied fruit into the popular king’s cake (bolo rei).

Bolo rei was introduced in Portugal in the second half of the 19th century by Confeitaria Nacional, a pastry store in downtown Lisbon. It was based on France’s “gateaux des rois,” a royal cake forbidden during the French revolution until pastry chefs renamed it the “people’s cake” (gateaux des sans culottes).

Over time, Confeitaria Nacional’s recipe was imitated and adapted, and bolo rei became an integral part of Portuguese culture. So much so that, when the monarchy was abolished in 1910, the Portuguese parliament renamed it Republic’s cake. But the awkward name never caught on.

Pastry stores used to hide two objects inside the cake: a gift (a trinket or, in some cases, a gold coin) and a dried fava bean. The gift has been eliminated but the fava bean is still included. According to tradition, whoever gets it has to buy the next cake.

The custom of hiding a fava bean inside a cake originated in the ancient Roman festival of Saturnalia. The person who found the fava bean became king of the Saturnalia and served as the festival’s master of ceremonies.

If you’re in Portugal during the Christmas season, make sure you try some bolo rei. It’s a sweet piece of European history.