The term 'like a piece of CAKE' is an idiom that means something is very EASY to do. This phrase can be broken down into four crossword solutions: SWEET (5 letters), EASY (4 letters), SIMPLE (6 letters), and easyaspie (9 letters). SWEET refers to the fact that CAKE is a dessert, and is usually considered a treat. EASY and SIMPLE both refer to the ease of completing a task. Easyaspie is a play on words, combining the phrase 'EASY as pie' with the word 'CAKE'.