Oatmeal cake is making a comeback in American kitchens after decades of being forgotten. This rustic pastry, once the star of church gatherings, now appeals with its disconcerting simplicity: only 6 ingredients, no superfluous utensils. But what explains this sudden craze for this dessert that our grandmothers used to prepare with their eyes closed?

Some recipes never really disappear. This oatmeal cake,…


