The phrase "proverbial cake" is used to refer to something that is commonly or metaphorically known or talked about. It is like a symbolic representation of something that is well-known or widely recognized.
Sentences with «proverbial cake»
The proverbial cake is still going to be sweet, it's just a matter of how sweet. (thebalance.com)
And if they go to church once in awhile, well that's just icing on the proverbial cake for me. (religion.blogs.cnn.com)
That said, the tuna white bean dip with those lovely pitas is just the icing on the proverbial cake. (jenncuisine.com)