Would they settle for a daily menu in the sense of I assume you will have an idea before you go to bed of what you will serve the next day. Could that be written on a whiteboard or fancy chalkboard near the entrance so parents can read it.

Also stress to them that the menu reflects the likes and dislikes of the kids so it isn't necessary for them to worry about having to have a meal their child will like for supper as you will make sure there is something served their child can eat.

For sure a sample menu of the kind of foods you serve to show but then remind them that the menu will vary according to left overs, weekly sales, how often you get to go shopping etc.