Each January, French families unite around the frangipane-stuffed puff pastry known as galette des rois, an Epiphany staple now enjoyed throughout the month. Along with glasses of cider or Champagne, the assembled dig into their slices, carefully, in hopes of being designated king for the day by the presence of an inedible trinket known as the fève. Fève originally means fava bean, an allusion to similar winter solstice traditions dating back as far as ancient Rome, with favas signifying spring’s arrival. It wasn’t until the Middle Ages that the fava…