Six fire engines and around 40 firefighters tackled a fire at a restaurant on Church Road in Hendon.
The extraction system from the ground floor to the roof of the building was destroyed by fire. There were no reports of any injuries.
The Brigade’s 999 Control Officers took 25 calls to the blaze.
The Brigade was called at 1359 and the fire was under control by 1521. Fire crews from Mill Hill, Finchley, Hendon and surrounding fire stations attended the scene.
The cause of the fire is under investigation.