Five fire engines and around 35 firefighters were called to a fire at a maisonette on Strasburg Road in Battersea.
Part of the kitchen of a split-level maisonette on the fifth floor of the building was damaged by fire. One man left the building before the Brigade arrived. There were no reports of any injuries.
The Brigade's Fire Investigators believe the fire was caused by a portable hob which was left on top of the integral electric hob.
A London Fire Brigade spokesperson said: "You should never place anything that can catch fire near to the hob.
"Keep all objects, like tea towels, cloths and plastic bowls well away from the cooker and always check the hob is turned off when you've finished cooking."
The Brigade was called at 1309 and the fire was under control by 1342. Fire crews from Battersea, Chelsea, Fulham and Lambeth fire stations attended the scene.