With no second ingredient anywhere in the build, the choice of how long the cheese was aged does all the work, and Comté is precise enough to carry that weight alone. Comté is a pressed cooked-curd cheese from the Franche-Comté, 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 firm but supple, milky and lightly sweet; an aged one turns hard and granular, with a deep savory length and the small crunchy crystals of tyrosine that form as it matures. The build is a length of baguette, a thin spread of beurre demi-sel or none, and Comté cut into thick slices laid flat along the bread.
The logic follows from the cheese's body and its age. Comté holds its shape and does not run, so it gives the sandwich a solid, sliceable layer that you taste in clean bites rather than as a smear. With nothing else in the sandwich, the choice of age does all the work: a young wheel keeps it soft, rounded, and gently sweet, while an aged one gives it grip, a salt-driven savor, and the crystalline crunch that is the whole point of choosing an old Comté. The butter stays thin or is skipped entirely, because the cheese is already carrying the richness and the finish. Slice thickness matters: too thin and even an aged Comté reads flat, cut into honest slabs slightly thicker than a ham slice it holds its crunch and its long finish against the wheat.
The bread needs a firm crust because the filling brings no structure of its own, and the cheese is best near room temperature, where an aged wheel's nuttiness opens and the crystals stay distinct rather than waxy. A few crushed walnuts or a slice of firm pear sharpen an old wheel without crowding it; a young one needs only good bread and a little salt.
Variations move along the Jura cheese rack and the aging spectrum: a longer-matured Comté for a drier, sharper, crunchier sandwich, a young Beaufort from neighboring Savoie for a creamier, grassier reading, a Morbier for a softer center with an earthier note. Each is a recognizable adjustment of the same firm, sliceable idea. It belongs with the cheese sandwiches the catalog groups under Baguette Fromage, and its specific contribution is an aged crystalline cheese complete enough to need nothing built around it.