“The secret ingredient is love” (or “The secret ingredient is always love”) is a cooking saying that has been printed on many images. “The secret ingredient is (always) love…and butter” has also been printed on many images.
 
“Really good cooking, the kind that nourishes as well as fills, requires a secret ingredient—love” was printed in the Longview (TX) Daily News on June 25, 1954. On the animated television series The Simpsons, the episode “Flaming Moe’s” that originally aired on November 21, 1991, Professor John Fink said, “Brace yourselves, gentlemen.  According to the gas chromatograph, the secret ingredient is…  Love!?  Who’s been screwing with this thing!” “Making pork chops. The secret ingredient - is love. No, actually, it’s pepper. Lots of pepper” was posted on X/Twitter by Roseburg MacGuy on May 9, 2007.
 
“BTW, it doesn’t matter which dish you are doing, the secret ingredient is always love” was posted on the newsgroup rec.games.computer.ultima.dragons on November 4, 2003. “Just love, the secret ingredient is always love” was posted on X/Twitter by Becky L. on April 7, 2009. “The secret ingredient is always love” was posted on X/Twitter by Milagro Cantinas on January 27, 2011. “culinary challenged- lol! gotta tell you- the secret ingredient is always love- put some and the meal will be great & simple” was posted on X/Twitter by Precise Portions on November 8, 2011.
 
“Just finished reading a cookbook. Spoiler Alert: The secret ingredient is love. That and butter. Lots and lots of butter” was posted on X/Twitter by Stephen (call me Mister) E🥶💉💉💉💉💉 on May 3, 2022. “Love. The secret ingredient is love. And butter” was posted on X/Twitter by Coach Feeback 🏈 on June 21, 2022. “The Secret Ingredient Is Always Love and Butter” (on a sign) was posted on X/Twitter by Maha jobs on November 3, 2022. “The secret ingredient is love…and butter 👍” was posted on X/Twitter by DatGoobzilla on January 2, 2023.
 
         
Newspapers.com
25 June 1954, Longview (TX) Daily News, “Who Is Best Cook Hotly Debated Between Sees” by Gay Pauley (United Press), pg. 8, col. 6:
To which Miss (Marguerite—ed.) Piazza answers—“Really good cooking, the kind that nourishes as well as fills, requires a secret ingredient—love. Woman’s cooking for her family is done with love and solicitude.”
 
Wikipedia: Flaming Moe’s
“Flaming Moe’s” is the tenth episode of the third season of the American animated television series The Simpsons. It first aired on the Fox network in the United States on November 21, 1991. In the episode, Homer tells Moe Szyslak about the Flaming Homer, an alcoholic cocktail of cough medicine and fire that he invented. Moe steals Homer’s recipe, renames it the Flaming Moe and sells it at his tavern. The drink is wildly successful and boosts Moe’s business, but Homer is angry at him for his betrayal and seeks revenge.
 
Simpsons Archive 
Flaming Moe                             
Written by Robert Cohen
Directed by Rich Moore and Alan Smart
(...)
=========================
> Movie (and other) References
=========================
+ The Nutty Professor
- ``And the secret ingredient is… LOVE!’’ {rc}
(...)
Brace yourselves, gentlemen.  According to the gas chromatograph, the
secret ingredient is…  Love!?  Who’s been screwing with this thing!
—Prof. John Fink’s attempt to discover the recipe for a Flaming Moe,
  ``Flaming Moe’s’‘
 
YouTube
The Secret Ingredient Is LOVE
OWEN CA$H
Oct 3, 2017
(The Simpsons “Flaming Moe” episode segment is shown.—ed.)
   
Google Groups: alt.tv.simpsons
[8F08] Flamingo me
Raymond Chen
Mar 5, 1992, 11:58:06 AM
(...)
+ The Nutty Professor
- ``And the secret ingredient is… LOVE!’’ {rc}
(...) 
Brace yourselves, gentlemen. According to the gas chromatograph, the secret ingredient is… Love!? Who’s been screwing with this thing!
—Prof. John Fink’s attempt to discover the recipe for a Flaming Moe,``Flaming Moe’s’‘
   
Google Groups: alt.tv.simpsons
What’s Yer Altime Favorite Line
Jacob Stohler
Oct 31, 1996, 3:00:00 AM
Prof. Frink:
“The secret ingredient is… LOVE?!”
 
Google Groups: rec.games.computer.ultima.dragons
Mostly Brits?     
Ashikaga
Nov 4, 2003, 8:02:50 PM
(...)
To be honest, what makes a chief great is not the receipe (it’s only a small part of it), but the execution. So if it doesn’t turn out okay, while it may be Arcana’s recipe’s portion is wrong, but it also could mean you have no talent. Ouch! BTW, it doesn’t matter which dish you are doing, the secret ingredient is always love.
   
X/Twitter
Roseburg MacGuy
@RoseburgMacGuy
Making pork chops. The secret ingredient - is love. No, actually, it’s pepper. Lots of pepper.
5:38 PM · May 9, 2007
 
X/Twitter
Becky L.
@beckyinthesky
@SpeedySasquatch Just love, the secret ingredient is always love.
5:38 PM · Apr 7, 2009
   
X/Twitter
Milagro Cantinas
@Milagro_Cantina
The secret ingredient is always love
12:10 PM · Jan 27, 2011 from Toronto, Ontario
   
X/Twitter
Precise Portions
@PrecisePortions
@EvilTwinAlex culinary challenged- lol! gotta tell you- the secret ingredient is always love- put some and the meal will be great & simple:)
11:26 AM · Nov 8, 2011
   
X/Twitter
NickyD
@nicholasdaman
The secret ingredient is always love. ❤
10:43 PM · Jun 7, 2012
   
X/Twitter
Rachel
@rachelslurss
#jadeQuotes on finding out our smoothies ‘secret ingredient’ was boogers: “NO! The secret ingredient is always LOVE!! LOVE!!!!
4:36 PM · Jul 23, 2012
   
X/Twitter
markadooley
@markadooley
The secret ingredient is always love (or salt):  Trader Joe’s Recipe for Success http://buswk.co/MG9BnR via
@BW
11:07 AM · Aug 6, 2012
   
X/Twitter
Carrie McInturff
@CarrieHautamaki
The secret ingredient is always #love.
@OnoMauiGoodies #OMG #cupcakes
10:11 PM · Aug 29, 2012
   
X/Twitter
Jimmy Hollywood
@Smuggly_Mcweed
The secret ingredient is always love.
12:07 AM · Aug 31, 2012
   
X/Twitter
Pb Sosa
@Poohduh_b
“@slcordero: The secret ingredient is always love.” What secret ingredient are u talkin bout are u makin a cake?
1:41 PM · Oct 4, 2012
   
X/Twitter
Mitzula
@Mitzula
@invisiblewife the secret ingredient is always love…and by love I mean crack
12:03 AM · Oct 7, 2012
   
X/Twitter
🗝💋
@KeAnnaLeShai
The secret ingredient is always love. I think Spongebob be making love to those patties Idc as bubbly as he is, he’ll make love to anything.
9:14 AM · Dec 16, 2012
     
Google Books 
Recepten verzamelboek: the secret ingredient is always love
Front Cover
Imagebooks Factory BV, 2016 - 128 pages
   
OCLC WorldCat record
The Secret Ingredient Is Love. No, Really : Stake Sauce Series, Book 1
Authors:Lyssa Chiavari, RoAnna Sylver
eBook, English, 2017
Publisher: Kraken Collective Books, New York, 2017
 
Google Books
The Secret Ingredient Is Always Love: Kitchen Journal, Composition Notebook, 100 Lined Pages
Front Cover
Hannah Abedikichi
Independently Published, Jun 22, 2018 - Cooking - 102 pages
   
X/Twitter
🇺🇦Stephen (call me Mister) E🥶💉💉💉💉💉🇨🇦🤙
@elcheshen
Just finished reading a cookbook.
Spoiler Alert: The secret ingredient is love.
That and butter. Lots and lots of butter.
3:31 AM · May 3, 2022
   
X/Twitter
Coach Feeback 🏈
@JasonFeeback
Love
The secret ingredient is love.
And butter.
7:42 AM · Jun 21, 2022
   
X/Twitter
Maha jobs
@jobs_maha
The Secret Ingredient Is Always Love and Butter Sign Funny Wood Kitchen Wall Sign Funny Farmhouse Kitchen Wall Decoration Rustic Kitchen Wall Decor, 15.7 x 4.7 Inch (Black Words on White Background) https://mhjobs.xyz/the-secret-ingredient-is-always-love-and-butter-sign-funny-wood-kitchen-wall-sign-funny-farmhouse-kitchen-wall-decoration-rustic-kitchen-wall-decor-15-7-x-4-7-inch-black-words-on-white-background/
12:36 PM · Nov 3, 2022
   
X/Twitter
modedeluxe
@mode_de_luxe
The Secret Ingredient Is Always Love and Butter Sign Funny wood Kitchen wall Sign Funny Farmhouse https://ift.tt/X2nwcOS #moda #decor #fashion #trend #gift #amazon #ebay
(The saying is shown on a sign.—ed.)
5:37 PM · Nov 4, 2022
   
X/Twitter
DatGoobzilla
@DatGoobzilla
The secret ingredient is love…and butter 👍
3:04 PM · Jan 2, 2023
   
X/Twitter
Better Butter
@betterbuttercb
The secret ingredient is love… and butter. Always butter! 😉
12:25 PM · Feb 14, 2023
· 
X/Twitter
Ruthie’s Fueled by Good
@RuthiesForGood
The secret ingredient is love (and butter). 😉
#DallasEats #DFWFoodTrucks
11:36 AM · Jul 20, 2023
   
X/Twitter
Kierbets Designs
@kierbets
Valentine kitchen waffle weave “The Secret Ingredient is Always Love”  towels.
https://l8r.it/EZTv
#Valentinesday #pink #kitchentowel #love #romance #dishtowel #secret #theartofgifting #etsyhome #ingrediants #handmade #baking #hostessgift #farmhouseholidaydecor
4:40 PM · Feb 5, 2024