Lagana is a special Greek bread, flat and wide and eaten but one day a year, on Clean Monday at the start of Lent. Traditionally, lagana was unleavened, but now commercial bakers use yeast in its preparation. I learned to make this from a local baker in my neighborhood in Athens. Lagana claims another tradition that also dates to antiquity -it’s never cut with a knife, but broken off by hand, as iron connotes evil forces among superstitious Greeks.