A wooden peg pinned through one end of the casing announces the sausage before you taste it: that peg is the maker's mark of the Morteau, one large smoked sausage standing on its own. The saucisse de Morteau is a fat Franc-Comtois pork sausage, coarsely ground, tied off with that peg, and smoked slowly in a high wood-fired chamber until it is dense, deeply coloured, and unmistakably woody. It is poached or simmered through whole before it goes near bread. The build is a sturdy crusted loaf split lengthwise, a thin spread of butter if anything, the cooked Morteau sliced into thick coins and laid along the crumb, with little else so the smoked pork is the whole sandwich.
The logic follows from the size and the smoke. The Morteau is the larger, plainer Franc-Comtois sausage: where its slimmer neighbour leans aromatic with caraway and cumin, the Morteau leans dense and woody, the slow smoke the dominant note and the coarse fat the carrier behind it. Because it is broad, it slices into substantial coins that sit as defined bites rather than crumbling into the crumb, and the sandwich is stacked sparingly because each slice carries weight. The constraint follows from how assertive the smoke is: it is salty, fatty, and emphatic, so the build stays minimal, a little butter to bridge it to the crust, a stripe of strong mustard or a cornichon to cut the fat, nothing that argues with the wood. The sausage is best sliced from a piece cooked through and still warm, the fat supple and the smoke open; cold and firm against the crust it tightens and the woodiness flattens. The bread needs a real crust because the filling brings no structure of its own.
Variations stay inside the Franche-Comté larder rather than wandering off it. The classic regional pairing sets it against the hard mountain cheese of the same valleys, read separately as the Sandwich Comté-Saucisse de Morteau; the slimmer, caraway-and-cumin-spiced cousin is its own sandwich, the Sandwich Saucisse de Montbéliard, aromatic where the Morteau is woody. Each holds the smoked Franc-Comtois sausage as the fixed point and changes only the size, the spicing, or what sits beside it. It belongs with the cured-meat sandwiches the catalog groups under Sandwich Saucisson & Charcuterie. Its specific contribution is the larger wood-pegged sausage taken alone, dense and deeply smoked, the woody benchmark of the Franc-Comtois pair.