Abstract: Process for etching a pattern on a surface (S) of a sandwich roll or bun (P) after the roll or bun (P) has been baked, by applying to the surface of the roll or bun (P) a laser beam emitted from an etching unit (2) equipped with a laser source (20), said process implementing the following steps: focusing the laser beam output from the etching unit (2) with an adjustable focal length between the exit of the etching unit (2) and a focal point (PF) of the laser beam; adjusting the focal length of the laser beam so that the surface (S) of the roll or bun (P) to be etched does not coincide with the focal point (PF); passing the laser beam over the surface (S) of the roll or bun (P) to be etched in order to produce the etch lines of the pattern, with a plurality of passes of the laser beam over each etch line; and placing the roll or bun (P) in a sealed package after etching.