The Sandwich Saucisson-Beurre is the cured answer to the Jambon-Beurre, and the swap changes everything that follows. Where the jambon-beurre rests on pale, gently poached Paris ham, this one rests on saucisson sec, the air-dried cured pork sausage that is firm, fatty, and concentrated in flavor. The three elements are a fresh baguette, a generous layer of barely-salted butter, and the saucisson sliced into coins and shingled along the crumb. As with the ham version, there is nowhere for any of them to hide.
The butter is the load-bearing component here, and more so than in the ham sandwich. Saucisson sec is dry by design and assertively salty from the cure, so a dry crust meeting a dry sausage gives you two firm things and no bridge between them. The butter is that bridge: cool, faintly sweet, it smooths the join, rounds the salt, and carries the cured pork's flavor across the wheat in a way the sausage alone cannot. The baguette has to be that morning's, crackling outside and open inside, because the structure of the sandwich is entirely bread and the meat lends it none. The saucisson is sliced thin enough to fold and shingle but thick enough to keep its chew, since coins cut too fine go waxy and lose the snap that is half the appeal.
It scales the way the ham version scales: a demi-baguette eaten standing at a counter, a full one wrapped for a walk or a train. Cornichons sometimes sit on the side to cut the fat, the same role they play next to the jambon-beurre.
Variations move across the regional curing shelf. A garlicky, black-peppered Auvergne style sharpens it; a finer grind reads smoother; a young Comté layered alongside the sausage pushes it toward cheese country. The bare, butterless picnic reading is the Sandwich au Saucisson, engineered for portability rather than this one's bread-and-butter balance. It belongs with the cured-meat builds the catalog groups under Sandwich Saucisson & Charcuterie, and its specific contribution is the butter doing what the cure makes necessary: bridging two dry, salty things into one sandwich.