Cooking snack foods

A method of cooking a snack food, the method comprising the steps of:

• a. providing a bed comprising a plurality of inert particles, a portion of the inert particles having a density higher than uncooked snack food to be cooked in the bed, and another portion of the inert particles having a density lower than or equal to cooked snack food that expands in the bed during cooking;
• b. heating and moving the particles in the bed to form a mobile cooking medium in the form of a bed of heated, mobile particles having a Froude number in the range from 0.01 to 0.5;
• c. providing a plurality of raw or partially raw snack food pieces in the cooking medium thereby to cook the raw or partially raw snack food pieces to form a plurality of expanded cooked snack food pieces, wherein the heated, mobile particles transfer heat into the raw or partially raw snack food pieces by thermal conduction;
• and
• d. separating the plurality of expanded cooked snack food pieces from the cooking medium.