Very good answer. Another good retort would be "We can't all be the Rain Man" or "Do you expect me to look like the Rain Man?". Most people know autism only as depicted in this movie and have no idea how autism looks like on the less extreme part of the spectrum. — Elmy 56 secs ago

Good answer, especially for the caveat. Order timing and triage are important in a commercial kitchen, so it's good to point out that the request, while reasonable, might be a moderate inconvenience for the staff. And, at higher-end restaurants it may be the case that an entire meal is intended to be experienced in a certain way-- at some places "filling your belly" is not really the goal, and it would seem odd to request just that while eating there. — Upper_Case 1 min ago