As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - CREW REPORTED SMOKE IN CABIN. EMERGENCY DECLARED, RETURNED ORD LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND BURNT SUBSTANCE ON BOTTOM OF FIRST CLASS OVEN. CLEANED OVEN. RAN BOTH ENGINES AND AUXILIARY POWER UNIT AND NO SMELL OR FUMES FOUND. SYSTEM GROUND CHECKED NORMAL OPERATION.