We would suggest a fire blanket
If your cooker were to set alight, we would recommend you use a fire blanket.
Turn off the heat (if you can do so safely) and place a fire blanket completely over the fire.
This smothers it causing the fire to consume what oxygen is left, allowing the fire to dwindle.
NEVER use water, this creates an explosion of steam which is dangerous.
You can find out more about fire blankets here.