This is a decidedly less-sweet kind of morning bun, topped with a lemony, cardamom-scented sugar for crunch and flavor rather than the typical icing or sticky goo of a cinnamon bun. Unlike most sweet buns, which tend to stale quickly, these stay soft and pillowy long after they cool. The buns are best the day they’re baked but will keep, stored airtight at room temperature, for up to 4 days. The recipe time factors in dough preparation. If you already have all-purpose enriched bread dough on hand, this is much swifter work.