The Sally Lunn is one of the rare entries on this catalogue where the bread is the entire argument and the filling is an afterthought. It is a large, round, enriched bun from Bath, somewhere between a brioche and a teacake, with a soft, light, faintly sweet crumb and a thin golden top, and it is built to be split horizontally and filled rather than sliced like a loaf. The defining decision is the dough, not what goes in it. An ordinary roll filled with cream is just a filled roll; a Sally Lunn split and filled is a sandwich whose lead is a bread rich enough with butter and egg that it barely needs anything between its halves to justify itself.
The craft is in the split and the restraint of what follows. The bun is cut clean through the equator so the two domes open into broad, even faces, and because the crumb is tender and slightly sweet on its own, the filling is kept simple and is usually spread, not stacked: butter alone, clotted or whipped cream, or a thin layer of jam, applied so it sits in the crumb without overwhelming it. The bread does the work a denser loaf cannot, holding a soft filling without going to paste because its own structure is light rather than absorbent, and it is most often warmed or lightly toasted at the cut face so the butter melts into the surface and the contrast of warm crumb against a cool spread becomes the point. Eaten with the hands over a plate, it sits closer to the tea table than the lunchbox, a sandwich whose richness is in the carrier rather than the cargo.
The variations stay inside the split-and-spread frame and trade only the dressing. The savoury version takes a soft cheese or a slice of cooked meat in place of cream; the sweet runs to lemon curd or honey instead of jam; the toasted-and-buttered plain bun is the form at its most essential. Its near relatives are the other enriched West Country teacakes, the Bath bun and the lardy cake, the same rich-dough instinct shaped differently. Each deserves its own article rather than being crowded in here.