When I was a kid, birthday cakes could be dangerous. Some mothers would fold pennies and nickels into the batter. “For good luck,” they’d say, popping it into the oven. I believed the good luck part. Especially if the mother was married to a dentist and one of us kids cracked a tooth biting down on the Queen’s crown or the Beaver’s tail. But that didn’t happen very often. Most of us would dig safely though our slices of birthday cake, hunt down those coins and go home with chocolate smeared faces and sticky fingers — clutching small windfalls to stash in our piggy banks.