The Jambon-Comté is a ham sandwich organized around a single cheese, and the cheese is a precise one. Comté is a pressed cooked-curd cheese from the Jura, made from raw cow's milk and aged in cellars for anywhere from a few months to well over a year. A young Comté is supple, milky, and mildly sweet; an aged one turns firm and granular, with a deep savory edge and the small crunchy crystals that form as it matures. Which Comté goes into the sandwich determines what kind of sandwich it is, and a counter that names the cheese is telling you that the choice was made on purpose.
The build is a baguette, a thin spread of beurre demi-sel, slices of jambon de Paris, and Comté shaved or cut into thin slices laid over the ham. The logic is contrast within a narrow range. The boiled ham is pale and gentle; the Comté is dense and savory, with a long finish the ham does not have. A younger Comté keeps the sandwich soft and rounded; an aged one gives it grip and a salt-driven length that lingers past the last bite. The butter is restrained here because the cheese is already carrying the richness, and too much would flatten the contrast it exists to create.
The craft is in cutting the cheese to the right thickness and not crowding it. Comté sliced too thin disappears against the ham; cut into slabs it overwhelms the bread and turns the sandwich one-note. A few well-judged slices, slightly thicker than the ham, hold their own without burying the baguette. The bread still has to be fresh, the crust still has to have bite, and the sandwich is still best eaten within minutes of being made rather than held through the lunch service.
Variations move along the Jura cheese rack and the aging spectrum: a more matured Comté for a sharper, drier sandwich, a Morbier for its softer center and earthier note, a young Beaufort from neighboring Savoie for a creamier, grassier reading. Each is a recognizable adjustment of the same idea, the Jambon-Beurre carrying a named mountain cheese instead of standing on butter alone.