Pruimenvlaai for the coming of Lent

In my birth town of Antwerp we eat pruimenvlaai (prune tart) on Ash Wednesday. It is the last day of Carnival, the day before Lent, and the day when Catholics receive a black ash cross on their forehead as a sign of penance. Many people claim that the prune tart is connected to Ash Wednesday because the prunes are black. Others say prune tart was considered a poor man’s food, so it was suitable to eat before Lent. Prunes, however, have never been a poor man’s food and, as common as the ingredient might seem today, it is hardly cheap.