Abstract: Processes and equipment for preparation and cooking of edible materials, particularly for the automatic slicing and deep frying of vegetables, especially potatoes, to form crisps. The procedure comprises the steps of forming unwashed and undried slices of the edible material, individually feeding the slices without washing and drying into a bath of hot cooking oil, then when said slices subsequently float to the surface of the oil due to the formation of steam bubbles on the slices forcibly submerging the slices in said hot cooking oil for a further period in which cooking of the slices is substantially completed to give the slices a crisp consistency, and finally removing the cooked slices from the cooking oil and dispensing the cooked slices.