When we hiked mountain trails along the Amalfi Coast several years ago, we marveled at the fist-sized lemons hanging off the cliffside trees. We didn’t know at the time, but they were begging to get zested and squeezed into this ultramoist and puckery lemon cake. While this lemon-lover’s dessert comes from the region, it doesn’t require Italian lemons. The supermarket variety will do just fine. Who knows the real heritage of this cake. It has relatives all over the world. The English call it a “lemon drizzle cake.” It starts out as a classic butter cake—rich, fluffy, golden, and fairly easy to make. The jolt of flavor comes from the lemon syrup that gets…