Fire services were called to the fire on Dover Road in Walton at 9.14am yesterday (June 8).
Firefighters found flames in the kitchen of the flat caused by the cooker which was switched on and had heated up a greased baking tray.
Crews from Dogsthorpe and the north roaming fire engine both attended the scene and recorded the fire as accidental.
Station commander Gareth Boyd, the officer in charge of the incident, said: "The crews arrived at the incident and quickly established the flat was smoke logged.
"Firefighters entered the flat and found the fire was in the kitchen. The cooker has been switched on accidentally and heated up a greased baking tray.
"It is quite easy to brush against an electric cooker and switch it on accidentally, especially if the kitchen itself is small. It is important to make sure the appliance is switched off at the wall when not in use.
"Luckily this happened during the day when no-one was at home, rather than at night when the occupants were asleep. Either way, it shows the importance of having working smoke alarms fitted in the home and testing them regularly to make sure they work."