As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: CATERING LEFT PAPERS IN OVEN RACK, WHEN OVEN WAS TURNED ON TO HEAT FOOD THE PAPERS STARTED TO SMOKE WITH SMALL IGNITION. FLIGHT ATTENDANTS EXTINGUISHED WITH HALON. CLEANED AND PERFORMED OPERATIONAL TEST PER AMM 25-35-00. OPERATIONAL TEST IS OK.