Six fire engines and around 40 firefighters were called to a restaurant fire on Nutford Place in Marylebone.
Half of the ground floor restaurant below residential flats was damaged by fire. There were no reports of any injuries.
Station Officer Will Thompson, who was at the scene, said: “Crews arrived to find the restaurant alight with heavy smoke coming out of the building.
“A number of people were already out of the property when firefighters arrived and a systematic search was carried out.
“Swift initial actions from crews meant that the fire was quickly contained and stopped from spreading to the flats above and to neighbouring properties.
“Road closures were in place whilst firefighters worked to make the scene safe.”
The Brigade was called at 2248 and the fire was under control by 2357. Fire crews from Paddington, Euston, Soho, Kensington and North Kensington fire stations attended the scene.
The Brigade's Fire Investigators believe the fire was caused by cooking on the grill in the kitchen igniting fat deposits in the extraction system.