Mess On a Plate

"The challenger's ugly food has shown us that even hideous things can be sweet on the inside." [Begins to cry]

—Morbo, Futurama

A common saying among chefs is that "you first eat with your eyes." Cooks who produce this food apparently expect everyone eating to be blind.

It could take several forms - maybe it's collapsed into an indistinct brown or grey glop in a bowl. It would be a misshapen mound that vaguely looks like a cake. Random tentacles and eyes could be mixed in. If it's a cake, expect the decorations to be something out of the wildest imagination of a Nightmare Fetishist (whether or not the cook is actually one).

Keep in mind, of course, that this is completely distinct from a Lethal Chef or a Cordon Bleugh Chef - in fact, while food such as this is a frequent indicator of one of those two tropes, it's increasingly common to have overlap with Impossibly Delicious Food. It can overlap with Alien Lunch in appearances.

Can easily be Truth in Television - even in culinary schools, presentation is taught distinct from flavor, and it's fairly common for students to be much better at the latter.

Examples of Mess On a Plate include:

Anime and Manga

Tina from Ai Yori Aoshi - as Taeko discovered, Tina's inability to make anything looking good did not stop her from making food that actually tastes good.
Ryo from Otomen can occasionally (usually with Asuka's help) produce food that tastes decent. However, it will invariably look terrible.
Naru from Love Hina is known to produce food that looks awful but tastes good.
Asuna's first cake from the first anime adaptation of Mahou Sensei Negima. The second came out looking much better. Appropriate, as she's anExpy of the above.
Akane of Ranma ½ combines this with Lethal Chef - she creates food that is both inedible and hideous to look at. The only exception is her curry, which is edible (if bland)... but still hideous to look at.
Axis Powers Hetalia: England's food is mostly portrayed as an indeterminable black mess. Sometimes it even gets pixeled out to emphasize this.

Film

Starship Troopers (the movie) had a scene where the recruits are in the chow line, loading up their trays with what appear to be different colors of pudding. Emphasized by one of them holding a ladle full up at eye level and disgustedly pouring it out.
In Accepted, Glen creates a recipe he calls "Wads" that look like a well, wad of melted chocolaty goo. The others recoil at first, but once they get brave enough to taste them they rave that it's the greatest thing they've ever eaten.
The eyeball soup in Indiana Jones and the Temple of Doom.
In the Star Trek parody, Galaxy Quest, the Thermians attempt to replicate food from the actors' supposed home world. Doctor Lazarus' dish is a bowl of clear liquid filled with live beetles.
In Better Off Dead, Lane's mother serves up a plate of homogenous green goop -- that crawls away as fast as it can when Lane pokes it with a fork.

Literature

Molly in Moon Over Soho whenever she tries to cook anything that isn't High Victorian, on one occasion producing what is described as rubbery vulcanised mass that looks like one of those novelty vomit mats sold in Joke Shops (it was supposed to be lightly poached eggs in hollandaise sauce).
In one of the Myth Adventures stories, Skeeve, having never seen spaghetti, describes it as white worms or snakes covered with blood red sauce.
- Also from the series, Pervian food is described as being difficult to keep from crawling away from your plate. The rest is left up to the reader's imagination.

Live-Action TV

A popular classic Sesame Street skit has Ernie making a plate of mashed banana with ice cubes and gravy on it. Bert is disgusted by its mere appearance, but guess what Oscar thinks?
Star Trek occasionally has food that is unappetizing to behold. The Klingon dish Gahkt comes to mind, though Klingons are Proud Warrior Race Guys and it may be meant as showing how tough they are that they eat things that look frightening to most sentients.
Babylon 5 occasionally has food that is unappetizing to behold. The dish Spoo comes to mind.
Johnny Bago: When Johnny temporarily joins a circus (not that he wanted to join, he was blackmailed into it) the owner/ringmaster literally feeds the circus workers on garbage leftover from the previous day's crowds, all of which looks like scoops of brown blegh.

Music

Sugarhill Gang's "Rapper's Delight" has one verse about dealing with the intersection of this and the usual wares of a Lethal Chef: "I don't care what these people think I'm just sittin' here makin' myself nauseous with this ugly food that stinks!"
"School Cafeteria", one of "Weird Al" Yankovic's first songs (written in 1976, released in 1979) is a two-minute, twelve-second paean to the stereotypical source of all manner of messes on plates -- complete with descriptions of some of the dishes they've made.

Newspaper Comics

Frequently produced by Calvin's mom in Calvin and Hobbes.
FoxTrot: Surprisingly, not Andy's cooking, though it frequently involves tofu. The cafeteria glop qualifies, however.

Webcomics

Schlock Mercenary has a restaurant chain that serves 'smutto', a combination of corn smut (basically mold), and natto (fermented soybeans). It's so vile that even Schlock (who'll eat pretty much anything) hesitates before eating it.

Ebbirnoth: It's not just corn and soy. It's also a bacteria colony fighting off a fungal infection. Smutto is a little of germ warfare disguised as a side dish.

Western Animation

Bender's final presentation in the Futurama episode "The 30% Iron Chef."

Morbo: The challenger's ugly food has shown us that even hideous things can be sweet on the inside. [Begins to cry]

Real Life

The traditional military dish of this sort is chipped beef on toast--better known to soldiers as "shit on a shingle."
The Hawaiian islanders have a dish called "poi", which is made from the root of the taro plant. It is purple, and has the consistency (and taste!) of Elmer's glue.