easy peasy

Reader's Digest 12/1月合併号の記事 'New Rules of Laundry' からの引用です。

New Rule #1: Don't let your clothes tell you what to do.
Our clothes are bossy. Their tags bully us into time-sucking techniques, and before we know it, each article of clothing is trying to tell us what to do. Easy peasy is my mantra.

・Oxford English Dictionary: Very straightforward and easy (used by or as if by children): ‘they insist the new tax forms are easy-peasy’
・Collins Dictionary: very easy; presenting no difficulty at all: very easy; presenting no difficulty at all: Difficulty levels can be adjusted from easy-peasy to fiendishly difficult.
・Cambridge English Dictionary: very easy: It would be easy-peasy to talk about introducing lots of lovely clean electricity generated by wind or whatever we liked if we charged the consumer twice as much.

ごろ合わせから出来た表現でしょうね。