PURPOSE: To prepare an expanded instant food giving natural and luxury appearance by including a liquefied gas in a food slurry and subjecting the food to heat-expansion and drying.

CONSTITUTION: A food slurry such as a scrambled egg, preferably a slurry at least containing an undenaturated heat-coagulable protein and having a water-content controlled to a quasi-bound water region, is mixed with a liquefied gas such as liquefied carbon dioxide gas to impart the slurry with moldability by the viscosity-increase caused by cooling. The cooled slurry is formed and the formed product is heated, expanded and dried e.g. by microwave dielectric heating to obtain the expanded food.