Turducken (turkey + duck + chicken) is a popular Thanksgiving meal. There have been many imitations made without meat.
 
“What next, vegetarian Turducken?” was a newspaper headline in November 2001, but it was a hypothetical question. “‘Tofu-cken’ (vegan turducken)” was cited in 2003. “And now, ladies and gentletwits…introducing the vegan turducken!!!” was cited on Twitter on July 17, 2007.
 
“A veggie turducken” was cited on Twitter on November 24, 2008. “Turducken sure, but what about Veggieducken?” was written by Dan Pashman on Twitter on November 5, 2012. Pashman gave the recipe to his “Veggieducken” (aka Squashleekotato Roast) on The Sporkful a few days later.
 
“I….need to make a vegetable turducken, you know an eggplant is large enough to fit things in, or combo vegducken” was cited on Twitter  on June 14, 2012. “2015 is the Year of the Vegducken” by Ali Slagle was published on Food52 on November 3, 2015.
 
             
Eat Dangerously
April 4, 1999 (Undated. This Google date might not be accurate.—ed.)
Papplequatince - (pear stuffed with an apple stuffed with a loquat stuffed with a quince…think vegetarian turducken but with pomes)
 
10 November 2001, The Capital Times (Madison, WI), “The Talk” by Doug Moe, pg. 2A, col. 1 headline:
What next, vegetarian Turducken?
 
tribe
“tofu-cken” (vegan turducken )
Showing photo 21 of 22 total.
posted by Beverly on Sunday, November 30, 2003
 
Twitter 
dana j. robinson
‏@skampy
and now, ladies and gentletwits…introducing the vegan turducken!!!  http://tinyurl.com/yq37rq
7:23 PM - 17 Jul 2007
 
Twitter
Eric Tatro
‏@erictatro
@jenny2003: The vegan version of the turducken: Tofu stuffed with seitan s/w textured vegetable protein. Not nearly as tasty.
11:50 AM - 17 Nov 2008
 
Twitter
Kimberly
‏@WalkingHorse
@BlogWellDone a veggie turducken.  He says ” so that’s like tofu, wrapped in tofu, wrapped in tofu. cool” LOL You had to be there. 😊
11:12 PM - 24 Nov 2008
 
Twitter
motasteinchez
‏@natters1210
Veggie equivalent of turducken = tofucken.
1:03 PM - 25 Dec 2008
 
Twitter
tracey falk
‏@traceyfalk
@andmiriam like the Turducken of the vegetable world ... hmm, Garshroomion? That’s a mouthful, literally.
11:57 AM - 21 Jan 2011
 
Twitter
Curt Smith
‏@curtsmith
@JaniceWhaley squeggplini - it’s the turducken of vegetable dishes 😊
3:29 PM - 21 Nov 2011
 
Twitter   
Jean. Meaty Bones
‏@Adaser
@WasabiFlux i….need to make a vegetable turducken, you know an eggplant is large enough to fit things in, or combo vegducken
4:37 AM - 14 Jun 2012
 
Twitter
Dan Pashman
‏@TheSporkful
@andrewzimmern Turducken sure, but what about Veggieducken? http://ow.ly/f2z0i
2:08 PM - 5 Nov 2012
 
The Huffington Post
Veggieducken: The Vegetarian Turducken Your Thanksgiving Table Needs (VIDEO)
Posted: 11/15/2012 9:19 am EST Updated: 11/14/2013 11:08 am EST
(...)
Behold, the Veggieducken. Yep, we’re talking vegetarian turducken here, and if you’re looking for a veggie-friendly show-stopper, look no further. Vegetarian Thanksgiving might never be the same.
   
The Sporkful
Veggieducken: Step-by-Step Recipe and Photos
Posted by Dan Pashman
Nov 16, 2012
     
NPR
The Veggieducken: A Meatless Dish With Gravitas
NOVEMBER 18, 2012 5:52 AM ET
Vegetarians don’t need your sympathy on Thanksgiving, says Dan Pashman, host of a food podcast and blog called The Sporkful.
(...)
On vegetarians’ reaction to the Veggieducken
“They are very impressed. Absolutely. You know, it’s funny, because vegetarians do get a little defensive when you suggest they’re missing out, but when I explain it to them this way, it’s like, yes, I get it, you don’t have to eat turkey to have a great Thanksgiving meal, but you guys are missing out on this event.”
   
Fritinancy
November 20, 2012
Veggieducken
Attention, thoughtful Thanksgiving cooks! This year, don’t make your vegetarian guests endure a wan simulacrum of the big bird (yes, I’m looking at you, Tofurky®). Instead, serve them a true pièce de résistance: the veggieducken, a k a “vegetarian turducken.”
 
Twitter
Matt Patterson
‏@fidothe
Vegducken’s Revenge http://instagr.am/p/Sa2lpQFc-s/
10:49 AM - 24 Nov 2012
   
Slate
NOV. 24 2014 1:46 PM
At Last, Vegetarians Can Truly Give Thanks
By Dan Pashman
In 2012, Dan Pashman, the creator and host of The Sporkful podcast and blog, unveiled a vegetarian Thanksgiving centerpiece the likes of which the world had never seen before: the “Veggieducken.” Pashman wrote about the Veggieducken for Brow Beat, and his explanation and instructions are reprinted below.
(...)
It’s inspired by the turducken, a chicken inside a duck inside a turkey, with stuffing between each layer. A Veggieducken is two sweet potatoes inside leeks inside a banana squash, with vegetarian stuffing between each layer.
 
Food52
2015 is the Year of the Vegducken
by Ali Slagle • November 3, 2015
Its name has yet to be confirmed—veggieducken? vegetable turducken? vegetableducken? squashducken?—but the trend is in full swing. (Move over, mom jeans.)
 
The premise is simple: You know a turducken? You stuff a chicken in a duck in a turkey. Now take that concept and make it vegetarian.
 
Unofficial sources (a.k.a. me) say the trend started with Dan Pashman, who created the Veggieducken in 2012 for his Cooking Channel web series Good to Know. The media went wild. The Kitchn, Huffington Post, NPR, and PETA (naturally) held on tight: It was a centerpiece-worthy vegetarian-friendly main dish—what a sign of the times! Dan’s squashleekotato—“two sweet potatoes inside leeks inside a banana squash, with vegetarian stuffing between each layer”–wasn’t a one-year gimmick, though.
   
epicurious
Meet the Vegducken, the Ultimate Vegetarian Main Dish for Thanksgiving
KATHERINE SACKS / 11.09.15
(...)
Turducken (a chicken stuffed into duck stuffed into turkey) is strange as hell, but at least it makes sense anatomically—each bird has a built-in cavity for the smaller bird to be stuffed into. Stuffing hard, raw vegetables into each other seemed nowhere near as easy. But then I realized I could cut the vegetables in half and scoop out the insides, creating a cavity for the next vegetable. I started with the biggest butternut squash I could find, and then looked for vegetables that might fit inside it. Eggplant was a natural choice, then zucchini after that. And to fit into a zucchini? A tiny scallion, obvs.