The Sandwich Rillons is the one in this family that is not a spread, and that distinction is the whole point. Rillons are chunks of pork belly, cubed large, salted, and cooked slowly in fat until the outside catches and crisps and the inside stays tender, then left whole rather than shredded into paste. Where rillettes pull apart into a spreadable mass, rillons keep their shape: dense, glossy cubes you bite into and chew. The build follows from that, a crusted baguette split lengthwise, the rillons split or pressed flat so they sit against the crumb, and little else, so the confit pork is what you taste. This belongs to Tours and the Touraine, the same pork country that sets the rillettes benchmarks.
The logic follows from the texture. A rillon is a solid piece, not a paste, so the sandwich behaves like a meat sandwich rather than a spread sandwich: the bread holds discrete chunks that need bracing, and the cubes are best halved or flattened so they meet the crumb instead of rolling out at the first bite. The exterior is caramelized and faintly bitter from the rendering, the interior soft and deeply porky, and the fat that coats each piece bridges the meat to the bread the way butter would in a leaner build, so no butter is wanted here. The flavor is rich and salty enough that the counterweight stays sharp, cornichons or strong mustard cutting through, perhaps a leaf of frisée against the heaviness. The bread needs a real crust and an open crumb, because dense cubes will tear a weak loaf and the structure has to come from the bread, not the filling. It eats best lightly warmed or at room temperature, where the fat is soft and the crisp edges still read; chilled hard, the cubes go firm and waxy and the contrast that defines them is lost.
Variations stay on the Touraine pork shelf and move mostly by cut and crisp. A leaner-cut rillon reads firmer and less unctuous; a fattier, longer-rendered one is glossier and richer with a darker crust; pressed flat and griddled briefly, the edges sharpen further. Each holds the whole, cubed, crisp-edged confit pork as the fixed point, never letting it collapse into a spread, which is exactly what separates it from the rillettes it is shelved beside. The Sandwich Rillons belongs with the cured-meat sandwiches the catalog groups under Sandwich Saucisson & Charcuterie, the tradition that runs across France's regional curing shelves. Its specific contribution is texture as the dividing line: a potted pork that stays in pieces, eaten by the bite, where its shelf-mates dissolve into paste.