A cooking appliance having a cooking space with a micro-rough surface. The micro-rough surface is formed on a metal substrate. In order to better clean the micro-rough surface from dried or charred food material, the layer includes an enamel formed of a glass flux with separate crystal zones spaced from one another formed and embedded in the enamel. The crystal zones are formed by crystallizing portions of the enamel into crystalline phases, forming a rough superstructure with a plurality of fine structures on the surface of the superstructures.