Twenty five fire engines and around 150 firefighters were called to a fire at The Mall shopping centre on Selborne Walk in Walthamstow.
Part of the first floor of the two-storey building was damaged by the fire and more than half of the roof was destroyed. There were no reports of any injuries.
Station Manager Steve Smith, who was at the scene, said: "There was a lot of smoke so we advised local residents to keep their doors and windows closed while crews tackled the fire.
"There were also local road closures in place so motorists were asked to avoid the area where possible."
The Brigade was called at 0740 and the fire was under control by 1218, and firefighters remained on scene damping down deep seated pockets of fire throughout the evening.
Fire crews from Walthamstow, Leyton, Tottenham, Leytonstone, Homerton and surrounding fire stations were at the scene.
The cause of the fire is under investigation.