cooking with gas vs kosher

cooking with gas

phrase
  • Functioning particularly effectively; achieving something substantial. 

  • With the updated software, I was really cooking with gas. I got the project done in half the time. 

  • Used other than figuratively or idiomatically: see cook, with, gas. 

kosher

adv
  • In a kosher manner; in accordance with kashrut. 

verb
  • To kasher; to prepare (for example, meat) in conformity with the requirements of the Jewish law. 

adj
  • Fit for use or consumption, in accordance with Jewish law (especially relating to food). 

  • In accordance with standards or usual practice. 

How often have the words cooking with gas and kosher occurred in a corpus of books? (source: Google Ngram Viewer )