It's a misquote of the common idiom "let them eat cake" > "Let them eat cake" is the traditional translation of the French phrase "Qu'ils mangent de la brioche

It's a misquote of the common idiom "let them eat cake" > "Let them eat cake" is the traditional translation of the French phrase "Qu'ils mangent de la brioche", said to have been spoken in the 18th century by "a great princess" upon being told that the peasants had no bread. The French phrase mentions brioche, a bread enriched with butter and eggs, considered a luxury food. The quote is taken to reflect either the princess's frivolous disregard for the starving peasants or her poor understanding of their plight. https://en.wikipedia.org/wiki/Let_them_eat_cake https://en.wikipedia.org/wiki/Let_them_eat_cake