Some—but certainly not all—Buddhists have a vegetarian diet. A Chinese dish is “Buddha’s Delight” (sometimes “Buddha Delight”) or “Buddhist Delight” (sometimes “Buddhist’s Delight”). The many vegetarian ingredients vary with each preparation.
 
The vegetarian dish became popular in Chinese-American restaurants in the 1960s. “Buddha’s Delight” was printed in the book The Pleasures of Chinese Cooking (1962) by Grace Zia Chu, who also instructed Chinese cooking classes in New York City. “Buddhist’s delight” was printed in the New York (NY) Times on April 19, 1963, when it was a dish at the Mandarin East, 1085 Second Avenue at 57th Street. “Buddha’s delight” was printed in the New York (NY) Times on October 17, 1964, when it was served at the New Shun Lee, 2450 Broadway near 90th Street. “Buddhist Delight (loo Hon Opp)” was printed in the Pittsburgh (PA) Post-Gazette on February 2, 1965, when it was served at the Chinatown Inn, 522 Third Avenue.
     
Buddha’s Delight (Lo Hon Jai in Cantonese) is a popular dish on Chinese holidays.
 
       
Wikipedia: Buddha’s delight
Buddha’s delight, often transliterated as Luóhàn zhāi, lo han jai, or lo hon jai, is a vegetarian dish well known in Chinese and Buddhist cuisine. It is sometimes also called Luóhàn cài (simplified Chinese: 罗汉菜; traditional Chinese: 羅漢菜).
 
The dish is traditionally enjoyed by Buddhist monks who are vegetarians, but it has also grown in popularity throughout the world as a common dish available as a vegetarian option in Chinese restaurants. The dish consists of various vegetables and other vegetarian ingredients (sometimes with the addition of seafood or eggs), which are cooked in soy sauce-based liquid with other seasonings until tender. The specific ingredients used vary greatly both inside and outside Asia.
     
Wikipedia: Buddhist vegetarianism
Buddhist vegetarianism is the belief that following a vegetarian diet is implied in the Buddha’s teaching. In Buddhism, however, the views on vegetarianism vary between different schools of thought. According to Theravada, the Buddha allowed his monks to eat pork, chicken and fish if the monk was aware that the animal was not killed on their behalf. The Mahayana schools generally recommend a vegetarian diet; according to some sutras the Buddha himself insisted that his followers should not eat the flesh of any sentient being. Monks of the Mahayana traditions that follow the Brahma Net Sutra are forbidden by their vows from eating flesh of any kind.
 
28 November 1962, New York (NY) Herald Tribune, “Chinese Cooking Can Be Taught in Classes” by Isabel A. McGovern, pg. 18, col. 7:
A former teacher at the China House, Mrs. Grace Chu, is the instructor at the Mandarin House School of Cooking, 135 W. 13 St. Madame Chu is also the author of “The Pleasures of Chinese Cooking,” published by Simon and Schuster in 1962.
(...)
For students who have completed the above course, more elaborate dishes and banquet fare will be presented, such as : (...) Buddha’s Delight, Pork Stuffed Cucumbers.
       
Google Books
Library Journal
Volume 87, Issue 4
1962
Pg. 3450:
(Review of the book The Pleasures of Chinese Cooking by Grace Zia Chu, published by Simon & Schuster in 1962.—ed.)
Recipes are arranged by groups: “Popular Dishes in Chinese-American Restaurants” (such as chop suey), “What Makes a Chinese Dish Chinese,” “Family Cooking, Chinese Style,” “Food Fit for a Chinese Gourmet” (Buddha’s Delight with tiger lily buds and dried tree ears!) and “Chinese Hors d’oeuvres.”
 
3 March 1963, Trenton (NJ) Sunday Times-Advertiser, “Chinese Cookery,” pt. 4, pg. 16, col. 3:
(Review of the book The Pleasures of Chinese Cooking by Grace Zia Chu, published by Simon & Schuster in 1962.—ed.)
There are such dishes with the exotic names of Gold Coin mushrooms, Buddha’s Delight (ginkgo nuts, tiger-lily buds, lotus roots, bamboo shoots as well as one small Irish potato), bird’s nest soup, shark’s fin and Chinese cabbage, lobster with black bean sauce, half-moon omelet with peas.
 
19 April 1963, New York (NY) Times, “Restaurant Review: Mandarin East Specializes in Spicy Food of Szechuan School of Cooking” by Craig Claiborne, pg. 29, col. 7:
(Mandarin East, 1085 Second Avenue at 57th Street.—ed.)
One of the interesting entrees on the luncheon menu is called Buddhist’s delight. It is an assortment of vegetables cooked in the Chinese style. The cost of a complete luncheon is $1.75.
 
17 October 1964, New York (NY) Times, “Food News: Vegetarians At a Banquet” by Craig Claiborne, pg. 32, col. 6:
(New Shun Lee, 2450 Broadway near 90th Street.—ed.)
It appears that the entree listed as Buddha’s delight was best received by the diners. This was a savory, stir-fried mixture of chestnuts, broccoli slivers, gingko nuts, mushrooms and fresh water chestnuts. The vegetables, particularly the chestnuts, were eminently edible.
 
29 November 1964, Boston (MA) Sunday Globe, “Pine Cone Fish, Bird’s Nest Pudding Raise Money for Library” by Ray Richard, pg. 47, col. 3:
Then came Shanghai steak with vegetables, pine cone fish (a sea bass shaped like a pine cone) and a plate of mixed vegetables called Buddha’s Delight. Named because Buddhist monks eat no meat, it contained, among other things, lotus roots, soy bean skins, bamboo strips, pea pods, water chestnuts and carrots. The carrots gave it color.
 
2 February 1965, Pittsburgh (PA) Post-Gazette, “It’s ‘Gung Hoy Fet Toy’ Time Again” by Zora Unkovich, pg. 10, col. 3:
(The Chinatown Inn, 522 Third Avenue.—ed.)
At Chinatown Inn, Buddhist Delight (loo Hon Opp) is one of the New Year specialties. The menu describes it as “a duck steamed until mellow, adroitly blended with vermicelli noodles, prosperity sea weed, soy bean curd, gingho nuts, lotus seeds, bamboo shoots, water chestnuts, and hearts of Chinese vegetables.”
   
29 October 1965, Back Stage (New York, NY), “Manhattan Tips” by Sheldon Landwehr, pg. 23, col. 1:
SHUN LEE DYNASTY
The newly opened Shun Lee Dynasty Restaurant at Second Avenue, corner 48th Street, is a far cry from the type of drab, second floor Chinese restaurants that started spreading over the city in the 20’s.
(...)
The menu lists all sorts of original dishes with suggestions like Happy Family (shrimp balls, meat balls, fish balls, shrimp, chicken, abalone, mushrooms, snow peas, etc.), Dragon and Phoenix (lobster and chicken cubes with bamboo shoots, snow peas and mushrooms), Buddha’s Delight…a vegetarian dish of water chestnuts, gingko nuts, carrots, dried bean curd, vegetable steaks and bok choy or scallops Wang style.
   
24 December 1965, The Record (Hackensack, NJ), “Mandarin Style Meals Served At New York City Restaurant; Chinese Dining Spot Opened In October Under The Direction Of Teaneck Man” by John H. Kuhn, pg. 27, col. 5:
(Shun Lee Dynasty at 900 Second Avenue.—ed.)
Other entries are: Buddha’s Delight, a vegetarian dish which includes all types of Chinese vegetables; sizzling rice with shrimp, bamboo shoots, water chestnuts, and peas; happy family, a combination of shrimp ball, meat balls, fish balls, shrimp, chicken, abalone, mushrooms, snow peas, bamboo shoots, and bok choy; and dragon and phoenix, in which lobster and chicken cubes are served with bamboo shoots, snow peas, and mushrooms.
 
20 January 1966, Pittsburgh (PA) Post-Gazette, pg. 13, col. 6 ad:
Loo Hon Opp (Buddhist Delight)
(The Chinatown Inn, 522 Third Avenue.—ed.)
 
14 January 1976, Washington (DC)

, “Buddhist Delight at David Lee’s Empress” by Ruth T. Pursglove, pg. D-8, cols. 2-3:
Buddhist Delight
1/4 cup each: thinly sliced celery and bamboo shoots
1/2 cup thinly sliced carrots
1 cup snow peas, blanched
4 water chestnuts
2 tablespoons peanut oil
1 teaspoon soy sauce
1 teaspoon sugar
1 tablespoon sesame-seed oil (available in Oriental food shops)
1/2 teaspoon cornstarch dissolved in 1/4 cup chicken stock
6 dried Chinese mushrooms
1/8 cup cloud ear mushrooms (tree fungi)
6 golden needles (tiger lily buds)
2 tablespoons hair seaweed
         
Serious Eats (April 2015)
Buddha’s Delight: The Vegetarian Stir-Fry to Rule All Vegetarian Stir-Fries
SHAO Z. 
If you search for vegetarian stir-fry recipes online, the first ones to come up usually contain a cast of familiar characters: string beans, carrots, tofu, bell peppers, and broccoli. There’s nothing wrong with stir-frying tofu and broccoli together, especially when it’s Kenji’s recipe for Vegan Crispy Stir-Fried Tofu With Broccoli, but there are so many other great meat alternatives worth adding to your stir-fry repertoire, and all of them can be found at your local Asian supermarket. If there’s one dish that brings them all together, it’s Buddha’s Delight (Lo Hon Jai in Cantonese).
 
Buddha’s Delight is particularly popular during Chinese holidays, such as Lunar New Year or Tomb Sweeping Day (Ching Ming).
 
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LEON DC
@leonUSA
You deserve some Buddha’s Delight this #SundayFunday. Cook up this vegan Chinese dish that’s traditionally eaten during the new year.
11:01 AM - 6 Jan 2019
 
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JennyC
@Rabi11381150
I liked a @YouTube video http://youtu.be/53DDtSuIHEw?a  日日煮烹飪短片 - 羅漢齋腐皮包-百寶福袋 Buddhist Delight Tofu Wrapped
1:48 PM - 7 Jan 2019