The 'greubons' folded through the dough are crispy leftover pork cracklings from rendering lard — a savory pastry built entirely around a butchery byproduct.
A rich, buttery pastry dough is studded with greubons — crisp bits of rendered pork fat — rolled and baked into a flat, flaky square. Bakeries in Vaud and across French-speaking Switzerland sell it as a savory grab-and-go snack, often still warm from the oven.