In 2015, Delphine Zalpetti, a self-taught chef, took over a former horse butcher shop (Chevaline) and transformed it into a buzzy niche for take-away dishes (Chez Aline). Customers queue for a brief, ever-changing menu of sandwiches, salads and desserts. Yet the item that has created the greatest buzz is Delphine’s jambon-beurre.

A sandwich that consists of a baguette slathered with butter and stuffed with ham—that’s it—the jambon-beurre is an anomaly in a city that’s associated with some of the most decadent and over-the-top dishes anywhere in the world. Yet it’s one of the most beloved casse-croûtes (snacks or light meals) among Parisians, inciting strong opinions and loyalties.

At Chez Aline, the baking of the baguettes is outsourced to a local baker who bakes them a few minutes longer than usual to obtain a particularly crispy crust. The butter is the salted type, from Normandy, and the ham is made in Paris, without nitrates or preservatives, and is sliced thin so as to melt on the tongue. The result is a sandwich that’s as much about texture—the crunch and spring of the bread, the creamy mouthfeel of the butter, the pull and melt of the ham—as it is about flavor.