Are the characters capable of having conversations with the author? Perhaps the "narrator" is a character and the purple proses is part of his/her characterization or style of speaking, and the characters are aware of this disembodied voice and the power it wields. While this is a bit difficult to pull off in a non-visual medium, it's not unusual. That said, a lot of visual media gets away with it all the time.
Consider the classic Looney Tunes short "Duck Amuck" where Daffy is made the play thing of a malicious (silent) animator who seems to only want to pester the poor duck. Represented by various drawling tools incuding a pencil, eraser, and paintbrush, the animator would constantly alter the world around Daffy or even Daffy himself to Daffy's protest. While he never speaks until the end, the dynamic was very unique even by Looney Tune's own brand of humor for the time, and is fondly remembered.
Other cartoons were keenly aware their medium and acknowledged that. In a short in Animaniacs, when doing a send up to the Pilgrims and the First Thanksgiving, the Warner siblings are stopping Miles Standish from hunting a Turkey for dinner, prompting Standish demand that the Warners "Give me the bird!" Yacko, denies the request, playfully suggesting that the Fox Network Censors wouldn't let them, before zipping away from a confused Standish.
The TV Show Samurai Pizza Cats had a narrator character who the onscreen characters were very much aware of and would often talk to and argue with. The show also regularly took digs at it's own production, such as the theme song admitting that the song exists because the show's script was misplaced and they were stalling for time (which... kinda actually happened. When the show was imported from Japan, the Japanese forgot to send the scripts for each episode, leading the U.S. production team to write the dub scripts whole cloth and they were very meta in their humor).
Disney's Hercules starts off with a disembodied voice of Charleston Hesston narrating the introduction of the story in a very elaborately animated museum. He is dramatically and stoically extolling the virtues of titular hero before he is interupted by the Muses (five characters that do interact with the story in limited capacity, though they serve as the narrative device of "The Greek Coir" for most of the film). The admonish Hesston for being too overly dramatic and that this story already needed their hand to lighten the mood. Hesston relents his narrative duties and Muses take over, transforming the dramatic pose into a Gospel inspired opening musical number.
An earlier Disney Film, the Many adventures of Winny the Pooh, has a narrator reading from a real world book as if a parent reading a bedtime story book. At one point, the narrator explains that the character of Owl had gotten into a long, rambling story that lasted several pages and that, for the sake of not boring the audience, he flips through those pages and resumes when something relevant to the plot comes back. The animation pulls away from the book's picture and the pages are actually flipped until the picture of the start of the next scene appears, showing if someone was to read the book, they'd actually read a multi-page monolog. Later, to show how bad the flooding of the 100 Acre Woods was, the viewer is treated to the flood waters not over overflowing the river banks, but also the picture's frame, and spilling onto the page and washing away the letters.
A mid-00s Disney Cartoon "Dave the Barbarian" also had a narrator who the characters were aware of and interacted with. The plot of the show's finale revolved around the villain realizing that the heroes always won because that was the story the narrator told. With this in mind, he kidnaps the narrator, and forces him to tell a story where the villain defeats the heroes. The heroes are only saved as all the strain caused the narrator to lose his voice, and his understudy had to take over... and the understudy had no interest in Dark Age High Fantasy genre, so narrates all the characters battling in a space opera setting... the characters are confused, but the heroes are at least fine with it as they still win.
In Emporer's New Groove, the film starts In Media Res with Kuzco narrating his sorry state of affairs and offering to catch the viewers up. Here, Kuzco is telling the story, but is not in control of the camera as he once admonishes the camera for it's large zoom out of a waterfall and it's sudden interest in a Monkey on a branch in the foreground as it chases a bug. Later, after a scene where Pacha comes home to his family, Narrator Kuzco comes back reminds the viewers that he's the character they should be focusing on, not Pacha and his family, and he's still knocked out in a sack on Pacha's cart (going so far as to vandilize the film by drawling a red circle around the sack and a giant red X on Pacha). Finally, when the film returns to the opening scene, Narrator!Kuzco begins to conclude by trying to shift the blame for his present state to other characters only to be interrupted by the onscreen Kuzco who reminds the narrator he just showed the audience the entire back story and they know that Kuzco got into this mess on his own and not because of anyone else's doing.
In all examples, the gag revolves around the reveal that the narrator is a character that the other story characters are capable of interacting with and treating him as such. The narrator is almost always flustered in this role, as they aren't used to the characters the are telling stories about actively back talking them or calling them on their own faults. It could be that the narrators are talking about how the heroes are about to begin their treak through the Deadly Pass of Doom only for the heroes to point out they could take the "Rainbow and Sunshine Short Cut", causing the narrator to argue his case for the Deadly Pass... and it's a poor argument... mostly because the narrator is so unused to be question by the characters he isn't practiced enough to counter their arguments.
It is very difficult to write in a book, because the narrative voice is tied closely with the decriptive actions, while in visual media, the narrator is independent of the action and tends to be more flowery in its description. One way to overcome this is if you adapt two narrative voices (I like to have my characters thoughts act as a first person narrator that compliments the Third Person Objective Narrator. That is, if the Third person is functioning as a security camera recording all the actions and dialog, than the first person is the character offering a Director Commentary about the events as they happened in a film.).