“Easy peasy” and “easy peasy lemon squeezy” both mean something that is very easy. It’s claimed that “easy peasy lemon Sqezy” was cited in 1964-65 print ads in the United Kingdom for Sqezy, a washing liquid. However, UK Press Online and The Guardian/The Observer digital archive do not show early printed citations; the earliest “easy peasy lemon squeezy” is from October 22, 1995 in The Observer.
 
The Oxford English Dictionary records “Easy-peasy” from 1966. “Easy-peasy-Japanesy” was cited in a 1982 book. “Can do. My specialty. Easy peasy, Japanesey, wash your face in Lemon Squeezy” was cited in a 1983 book.
 
A similar saying is “easy as pie.”
       
 
Star Brands Limited
Sqezy
It’s easy peasy with Sqezy!
We’ve given Sqezy a whole new funky and distinctive look a little bit retro but a lot about today - and we’d like you to give it a squeeze! From its origins in 1958 when Sqezy was launched as the world’s first washing up liquid in a plastic squeezy bottle, we’ve now brought it bang up to date. Although when you consider that 99.9% of people can complete the line ‘Easy peasy ..’ you’d hardly believe that it had ever been away! It’s even better now, and is so much faster and easier to use it really is ‘quick as a wink away from the sink!
 
AdSlogans
SLOGAN Easy peasy lemon Sqezy.
BRAND Sqezy
PRODUCT washing liquid
MEDIA Print
YEAR 1965
LOCATION UK
 
(Oxford English Dictionary)
easy-peasy, adj. (int. and adv.)
colloq. or Children’s slang (orig. and chiefly Brit.).
In childish or children’s use (esp. as int.): extremely easy, very simple. Freq. in easy-peasy lemon squeezy, and other phrases. Also as adv.: with ease, very simply.
1966   Bookseller 22 Jan. 185   He tried to do some magic but he could not spell the thing so he put a nought up and when Mr. Witch read it he said Easy-peasy, so he done the spell.
1976   Evening Standard 20 July 19 (in figure)  I’m short of money this week… How do I get to work?.. Easy peasy… I run to the station, leap the barrier, clobber the train driver, dress up in his clothes [etc.].
1987   Motor Cruiser June 25/1   It was no ‘easy peasy’ matter to get up to Maidstone.
1990   Independent 29 Oct. 14/1   We’ll do it easy-peasy lemon squeezy.
 
Google Books
Reading Interests of Children and Young Adults
By Jean Spealman Kujoth
Metuchen, NJ: Scarecrow Press
1970
Pg. 32:
(Along came a man called Mr. Crrm what was a wizard and he tried to do some magic but he could not spell the thing so he put a nought up and when Mr. Witch read it he said Easy-peasy, so he done the spell. )
     
Google Books
Brother of the More Famous Jack
By Barbara Trapido
New York, NY: Viking Press
1982
Pg. 81:
Hard clues for us older people, devised by Jacob in the style of The Times crossword puzzle, and more charitable clues for younger people, which Rosie said were easy-peasy-Japanesy.
 
Google Books
The Worst Journey in the Midlands
By Sam Llewellyn
London: Heineman
1983
Pg. 81:
“Can do. My specialty. Easy peasy, Japanesey, wash your face in Lemon Squeezy.” I have said some stupid things in my life, but that was the stupidest.
 
Google Books
The Trick to Money is Having Some
By Stuart Wilde
Sydney, Australia: Nacson & Sons, Pty.
1989
Pg. 191:
Easy-peasy-lemon-squeezy, any twit can work that one out.
   
Andrew Graham-Dixon Archive
Worlds Apart
Date: 12-11-1991
Owning Institution: Barbican Art Gallery
Publication: The Independent 1987 - 1999
(...)
The Cold War era of 007 post- dates the period covered in the Barbican’s show, which spans 1850-1930, but Fleming none the less demonstrated that at least one Victorian idea of Japan - as a land of easy peasy Japanesey sex with compliant oriental maidens - would die hard.
 
Google Books
English Historical Morphology and Word-Formation:
Loss Versus Enrichment
By Klaus Faiß
Trier: WVT, Wiss. Verl. Trier
1992
Pg. 96:
... easy-peasy(-lemon-squeezy)  ...
   
Google Books
Forcing the Factory of the Future:
Cybernation and Societal Institutions
By Bryn Jones
New York, NY: Cambridge University Press
1997
Pg. 165:
Easy-peasy Japanesy: flexible automation in Japan
At a Tokyo subway station an automatic machine failed to dispense a ticket in return for my coins.
     
OCLC WorldCat record
Easy peasy lemon squeezy
Author: Jo Seagar; John Stringer
Publisher: Auckland, N.Z. ; Random House, 2001.
Series: E.Z.P.Z cook, 1. 
Edition/Format: Book : Elementary and junior high school : English
Summary: Uses cartoon style illustrations to present step by step instructions for 57 recipes, including green gherkin dip, lemonade scones and microwaved scrambled eggs with cheese. Includes recipes suitable for vegetarians. Suggested level: primary, intermediate, junior secondary.
 
MarketingWeek (UK)
HHCL wins £3m Sqezy relaunch
Thu, 4 Jul 2002
Sqezy, the UK’s first washing-up liquid brand, has appointed HHCL & Partners to handle its £3m relaunch, following a competitive pitch against undisclosed agencies.
 
The relaunch will see the 38-year old brand, owned by chemicals company Buck UK, target young consumers in an effort to take on the market leaders, Unilever’s Persil and Procter & Gamble’s Fairy.
 
Buck UK managing director Gervase Cottam says: “We want to do something different in this market, to create a brand with a significant premium to the leader. Sqezy is designed to appeal to the young-at-heart.” The brand first appeared on the shelves in 1964 as “easy peasy lemon sqezy” washing up liquid.
 
OCLC WorldCat record
Easy peasy lemon squeezy
Author: Steve Martin
Publisher: London : Buster, 2012.
Edition/Format: Book : Juvenile audience : English
Summary: Packed with simple tips and tricks to boost kids’ brains and give them amazing memories. This title uncovers mnemonics and rhymes to help you to remember anything in a flash - from facts about physics, to sporting superstars, books and more.