This is about love, and abundance, and trust-building. What would you pay, if you could buy love, abundance and trust?
If your kids ask for another one (potato, cookie, peanut butter sandwich) I think it's helpful if you just say "Sure!" and make another one, even if you don't think they'll finish it, even if you think they'll be too full or whatever. As long as they're not eating someone else's share (and even so, if the other person agrees), it's not a big deal. If they don't finish, save the leftover for someone else. If they do finish and they're "too full" that's how they'll learn their capacity (which will change anyway as they get older).
Conversations with a parent are natural learning fodder. Natural learning doesn’t happen in a vacuum or in isolation. Those things aren’t so natural. 😊
In my experience, unschooling parents are more likely to say too much than not enough.
When it's easy to be calm and patient, anyone can do it.
The special service to a child, and the evidence of growth in a parent, is learning to be more calm, for the child's sake. The real patience is finding a way to quiet one's hurry, to slow down to a child's pace, for a while.