They say what was really "cooking" was black opium - three pounds of the narcotic coated with cinnamon, wrapped in clear cellophane plastic - part of an illegal drug shipment worth more than $100,000, CBS Los Angeles reported.
Sam Saeed Shariat, 63, a U.S. citizen, was arrested after the contraband turned up in his luggage as he arrived from Iran via Turkey, Customs and Border Protection (CBP) officials said.
Along with the opium found in the rice cooker and in a jar, nearly 2,000 prescription pills were seized from Shariat - methadone, alprazolam and valium.
CBP wanted to deliver a message.
"Smugglers who attempt to fool CBP officers with clever concealment methods, fool themselves," CBP Director of Field Operations Todd Owen said in a statement. "Our officers have extensive, ongoing training and very keen instincts for detecting unique concealment techniques."