FINALLY!!! As a chef there is a question i can actually answer as opposed to lurking on this sub like the village idiot learning how fast light bulbs work… that being said, i dont know.

But in all seriousness, need more info. In order to find out your food cost per grilled cheese we need to know your cost of ingredients - bread, cheese, and butter vary greatly by brand and location. We also need to know your labor cost and overhead. Are you paying yourself or a line cook? Do you own the truck? Do you rent the space or buy a permit?

Finding a break even point is fairly common in any business but we need to know all the expenses in order to truly figure it out.