Cut a round off this one and it sits on the board as a marbled disc, not a drape: that is the whole point, a charcuterie sandwich and not a ham one. The jésus is a Lyonnais dry-cured sausage, named for the region it comes from: a short, fat, coarsely ground pork saucisson in a wide casing, salt-cured and air-dried until it firms into a deep, marbled, pepper-and-pork block. It is a relative of the rosette but stubbier and more generous in fat. The components are a length of fresh baguette, optionally a thin layer of barely-salted butter, and slices of the cured sausage. The defining element is the jésus itself: a slow-cured, fat-marbled charcuterie with enough character to carry the sandwich on its own.
The craft is mostly in the slicing and the bread. Unlike a draped dry-cured ham, the jésus is cut into rounds, thicker than you would cut a thin ham, so each slice keeps the marble of lean and fat that gives it its texture. It is firm and rich, and the bread has to answer that: a baguette with a real crust that pulls against the bite, since the sausage brings flavor and density but no structure of its own. Butter is not mandatory here the way it is on a ham sandwich, but a thin spread bridges the salt of the cured pork and the wheat of the crust in a way the dry-on-dry version does not. A cornichon or a stripe of mustard supplies the acidity that keeps a fatty, salt-cured filling from coating the palate. Because the sausage is stable and dry, the sandwich holds up well, though it is still best within a short window of being built, while the crust has bite.
Variations are the wider cured-sausage shelf rather than mutations of the jésus: a Lyonnais rosette, an Auvergne saucisson heavy with garlic and pepper, and the rest of the regional charcuterie tradition, each cut and built the same way. Those carry their own articles rather than being crowded in here. The Sandwich au Jésus belongs to the cured and dry-sausage builds the catalog groups under Sandwich Saucisson & Charcuterie, and its particular contribution to that shelf is the jésus: a short, fat Lyonnais saucisson with the marble and depth to need very little around it.