As easy as pie
"As easy as pie" is a popular colloquial idiom which is used to describe a task or experience as pleasurable and simple. The idiom does not refer to the making of a pie, but rather to the act of consuming a pie ("as easy as eating a pie") which is usually a simple and pleasurable experience. The phrase is often interchanged with "piece of cake", which shares the same connotation.
- As easy as pie at Wikipedia