From one of the most well known deconstructive texts in America:
"That word you keep saying...I do not think it means what you think it means."
****Disclaimer: I do NOT wish to offend anyone with my post on Deconstruction. I actually spent a good long time trying to decide if I wanted to post or not, but I thought that given what has come before, I might have some way of finally giving back to a forum that has been very helpful to me. I am not implying that people who posted different ideas about what Derrida was looking to accomplish are somehow missing the point - it's just that Derrida is one of the most widely misunderstood, misquoted, and misapplied philosophers that I can think of (second only to Nietzsche, I think). This is mostly because Derrida is a tough read. There are full professors in my department who regularly misapply his work, and these are some smart cookies.****
I hate to do much more than lurk or ask questions on this forum, as I'm still such a neophyte in the kitchen, but I have done a good bit of work with Derrida. For anyone interested in getting a better understanding of how Derrida's usage of the term "deconstruction" works, read "Structure, Sign, and Play in the Discourse of the Human Sciences" from Writing and Difference. It is a term which is almost always taken to mean a literal destruction of meaning or segmentation of a text, leading to the idea that Derrida's project was about compartmentalizing in order to facilitate further analysis in a manner similar to that of Aristotle. While this is certainly a valid and useful approach, it is not what Derrida had in mind. Nor is looking at the "intersections" of disparate "elements" - that would be more appropriate to the Russian Formalists, or maybe Roland Barthes' earlier work (depending on how exactly you go about it). Oddly enough, Derrida was NOT interested in breaking things apart - that would really be the antithesis of how a decosntructive approach to literature works.
What Derrida meant by deconstruction could best be described as a questioning. A critic will examine a work with a special eye towards conflicts of logic or inconsistencies, and will then apply critical pressure at that juncture. The goal is not to expose the work as a fraud and thereby destroy its credibility or merit, but to understand the assumptions required by the work. Frequently this means questioning concepts which we all "understand", such as hospitality, mourning, or justice. Just as often, it means examining what seems to be an unresolvable opposition (nature vs. society, High vs. Low, etc.). It always means being critically rigorous, especially with regard to one's own tools of inquiry. Derrida encouraged the combination and adaptation of varied analytic techniques in order to get around the perennial roadblocks that each was unable to deal with on its own.
In short, deconstruction is a post-structuralist (post as in it came after, not necessarily replaced, earlier modes of inquiry) method of inquiry motivated by a need to pursue the sorts of contradictions and assumptions which, prior to Derrida's work, were mainly left unexplored (for various reasons).
What does this mean in the kitchen? Well, one of the most idiomatic moves of a deconstructive critic is to work with binary pairs: White and Black, Self and Other, Nature and Art. In the kitchen, one might think "Savory and Sweet" or "Edible and Inedible". I can think of many examples of pastry chefs building sugar creations that look like wine glasses, but while such an endeavor highlights the problem of that particular binary, it doesn't really deconstruct it. If the glasses were meant to be a part of dinner service (but not eaten), that would push the point a bit harder. If they were designed to flavor the beverage poured in them, the chef would be pushing that question even harder. Of course, whether or not that would "deconstruct" the binary of edible/inedible would be in the mind of the beholder (or the artist...or the critic...).
The few times I've seen "deconstructed" on a menu, the dish has been the same food I'd always get plated in a fanciful manner or prepared slightly differently. This dish would be de-constructed in the sense of structurally taken apart, but that alone isn't enough to activate the deeper sorts of thinking implied by the word as used in connection with Derrida's critical approach. This does not, however, mean that the dish is somehow a critical failure. It may be attempting a different type of deconstruction than that which Derrida modeled (which, now that I mention it, is really exactly the sort of thing towards which Derrida seems to be pointing us), or it maybe attempting a different sort of critical investigation all together.
I think that the real problem here (and I use "problem" as a way of denoting a point of profitable exploration) is that cooks don't have the vocabulary to talk about what we do that "artists" (notice the scare-quotes) do. There are a few exceptions, including earlier posters in this thread, but not enough to bring a standardized vocabulary to the discipline. The articulations above regarding what chefs are doing when they say they are "deconstructing" a dish are wonderful examples of the sort of metacritical inquiry that I would love to see appearing more and more frequently.
This definition of "Deconstruction" is VERY skeletal, brief, and simplified. If you'd like to talk more about it, please PM me.