The Crêpe Jambon-Fromage is the wheat-flour version of the savoury crêpe, and the form it takes when the Breton galette migrates out of Brittany. A standard sweet-style crêpe batter of milk, eggs, flour, butter, and salt is poured onto the crepière, spread thin, cooked through, and then filled, still on the iron, with a slice of jambon blanc and a handful of grated Emmental. The four corners fold inward as they do on a galette complète, the cheese melts under the residual heat, and the crêpe slides off the iron onto a plate or, more often, into a paper cone for the walk away.
The wheat-flour version reads as a softer, more forgiving cousin of the buckwheat galette. The crêpe itself is paler, slightly sweet from the milk in the batter, more pliable, and considerably more crowd-friendly than the slightly bitter galette de sarrasin: French children who do not like the assertive grassiness of buckwheat eat the Crêpe Jambon-Fromage instead, and so do the street-cart customers in cities that do not have a strong Breton crêperie tradition. The lack of an egg in the standard build is the other difference. Where the Galette Complète treats the yolk as a structural element, the Crêpe Jambon-Fromage stops at ham and cheese, on the theory that the wheat batter is rich enough to carry the sandwich on its own.
The sandwich shows up most frequently outside the crêperie context: at street carts in Paris, at the boulangerie counter at three in the afternoon, at the school-cafeteria menu, at the late-night kiosk in any French university town. The Crêpe Complète adds the egg and pulls the format back toward its Breton-galette parentage, and the sweet cousins (Crêpe au Sucre, Crêpe Beurre-Sucre, Crêpe Nutella-Banane) take the same wheat batter into dessert territory. The broader Crêpe & Galette Salée tradition covers the buckwheat side and the more elaborate savoury fills, and the Jambon-Fromage sits at the lightest, most portable end of the savoury repertoire: a wheat crêpe with two ingredients inside it, eaten warm, gone in under five minutes.