Promote your stall before the event with online orders. Bake, cook or make to order. Less wastage.
These online stalls can be stand alone as well as part of a fete. An online international food festival could work with international days at school or trivia nights where its is usually bring your own food. This could be supplemented with some “house specials’ where some people have a knack for making certain snacks or sweets which can be pre-ordered and paid for.
The menu could be displayed on the website: