Finding the precise history of the idiom, a piece of cake, is no picnic as I discovered.
It is believed that this phrase was invented in the 1870s during slavery in the southern states of America. As part of a dance or celebration organised by slave owners, black slaves would compete in ‘cake walks’, performing a dance which imitated and subtely [sic] mocked the elaborate and ostentatious gestures of the white slave owners. The most elegant couple/team would be given a cake as an award.
The “prize” for best dancing African American couple was a piece of cake, ergo...
The piece of cake that was awarded as the prize to the best couple/team, came to be known among the blacks as something very easy to obtain. (A sort of underhand and hidden insult to unknowing white ruling class.)
Now, I'm dubious whether slave owners and their families would generously share their dinner desserts with human "property", but it could be possible, and I admit I know next to nothing of the traditions that were held in Southern-American homes before the civil war, but according to History.com slavery was abolished in the US in 1865. So weren't African American slaves freed by the 1870s? Would slave couples continue to dance, and ridicule their "owners" (or "employers") in front of their very eyes?
The reputable site, Phrase Finder, suggests a different story
This phrase is of American origin. At least, the earliest citation of it that I can find is from the American poet and humorist Ogden Nash's Primrose Path, 1936:
"Her picture's in the papers now, And life's a piece of cake."
The choice of cake or pie as a symbol of ease and pleasantry is well represented in the language. Other phrases along the same lines include 'as easy as pie', 'a cake-walk', 'that takes the cake/biscuit'.
Vocabulary.com suggests that the origin of "cakewalk" is much older and includes the following definition
The Americanism cakewalk, used to mean "something easy," came first, in the 1860's — piece of cake wasn't used until around 1936. Both cake and pie have a long history in the United States as metaphors for things that come easily.
The search continues, according to American Heritage Dictionary, the idiom is British!
Something easily accomplished, as in “I had no trouble finding your house-a piece of cake”. This expression originated in the Royal Air Force in the late 1930s for an easy mission, and the precise reference is as mysterious as that of the simile easy as pie. Possibly it evokes the easy accomplishment of swallowing a slice of sweet dessert.
The following question, Idiom origins: "Piece of cake" and "Walk in the park" and "Close, no cigar"? is related but was closed for lack of research and also I suspect for being too broad. Furthermore, the only answer posted cites the 1870s origin written by Bloomsbury International as supporting evidence.
- Which of the sources cited above is closer to the truth?
- Is there an earlier citation than 1936, as cited by Phrase Finder?
- Is the idiom “piece of cake” American or British?