PlateUp!

Upgrade a hob blueprint into a danger hob (you might get a safety hob instead, if so try again). Once you have one, put it next to as many chairs as possible. Remember you can turn off chairs by holding X if your group size permits, to increase the chance that someone sits next to the hob.

When someone is sitting next to the danger hob, throw any food on it, so it catches fire and burns a customer. That will fail your run, but you can quit to the dashboard to restart the day if you want.