My repertoire of sweet lemon recipes is limited, but, as it happened, my friend, the Irish pastry chef JR Ryall, was in town, with his new cookbook “Ballymaloe Desserts,” for which I wrote the foreword. It contains a recipe for a homey hot lemon pudding. It's not a soufflé, but it has a light, airy feel. And, as it bakes, it separates into distinct layers, custardy on the bottom and spongy on top.