Before he knew it, his food was on fire.
That sounds crazy, why burn his food?
I ordered a steak which he didn't want to eat.
That was dangerous. You could have burnt down the kitchen and possibly the building. Please keep watch of how you are cooking the food.
It was just a bit of a char.
That char means that you let the fire get too out of hand, doesn't it? You need to be more careful and put out food before anything horrible happens, like a greater fire.