A method and apparatus for crisping the surface of a food substance in a microwave oven is disclosed. A thin film susceptor is positioned close to the surface of a food substance. The susceptor heats when it is exposed to microwave radiation. The susceptor preferably is a thin film of metal deposited on a polyester substrate layer. In one embodiment, heating the susceptor causes the polyester layer to shrink, thereby simultaneously creating openings in the susceptor to allow moisture to escape, and breaking the conductivity of the susceptor so that it becomes less responsive to microwave radiation and substantially "turns off." In an alternative embodiment, passageways are pre-cut in the thin film of metal. A single surface of the food substance is made crisp in this manner, while the opposed surface is exposed to the microwave oven atmosphere. It has been discovered that a consumer will perceive a food product as crisp if a single surface is made crisp in the manner according to the present invention, and the opposed surface is not soggy or mushy.