comfortably vs piece of cake

comfortably

adv
  • Easily; without effort or difficulty. 

  • In a comfortable manner. 

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 comfortably and piece of cake occurred in a corpus of books? (source: Google Ngram Viewer )