accomplishable vs piece of cake

accomplishable

adj
  • Capable of being accomplished; practicable. 

piece of cake

noun
  • Used other than figuratively or idiomatically: see piece, cake. 

  • A job, task or other activity that is pleasant – or, by extension, easy or simple. 

How often have the words accomplishable and piece of cake occurred in a corpus of books? (source: Google Ngram Viewer )