Thanks France, now that you mention it, it rings a bell. I think I had previously looked it up and discovered it to be a bean. However, I think your suggestion of 'lucky charm' is still better for the English reader, because few people would connect bean with la fève. I immediately connected it with the game of lottery and was perplexed, wondering what a bean has to do with the lottery game.

Wendy,
Here some information about the "lucky charm" in the Galette des rois.
https://www.lumni.fr/article/la-galette-des-rois-jamais-sans-la-feve

Fève is the name of a kind of haricot (bean). It's a delicious vegetable.
https://fr.wikipedia.org/wiki/F%C3%A8ve

Mark, I would tend to agree with France with the use of 'lucky charm'. For me the connection' with the 'lottery is self-explanatory, as it is immediately explained in the next unit. It describes what is in the King cake. (Not a bean, but a lucky charm).
(I don't understand the use of 'bean' ?)

I’d keep the connection with the lottery in vow of the next unit. If no one wins, the pot is carried forward to the next round.

Mark,
How about the lucky charm ?
ève nf (figurine de porcelaine) charm, lucky charm n
Pour un enfant, le plaisir de la galette des rois est d'avoir la fève.
For a child, the joy of a King cake is getting the lucky charm.