Claire Ptak made us this elegantly simple cake when we paid her a visit at Violet Cakes, her bakery-café in London. She explained that it is an old-fashioned British teacake known, rather plainly, as “seed cake” and that she first encountered it after moving from the U.S. to England in 2005. In addition to caraway, Ptak also includes lemon zest; its bright, fresh notes lift the richness of the butter, the sweetness of the sugar and the earthiness and anise-like hints of the seeds. She recommends serving the light, tender cake with glasses of Madeira. Leftovers will keep tightly wrapped at room temperature for up to three days.