Idiom for finally seeing something for what it really is

I also thought of "scales fell from my eyes". "Opened my eyes" may work, and variations on that such as "eye-opening", "eyes wide open," and "clear-eyed". "Saw the light" is another.

(My main source seems to be Todd Rundgren songs:)

https://somethingelsereviews.com/2012/01/13/one-track-mind-todd-rundgren-and-the-nazz-open-my-eyes-1968/

https://www.youtube.com/watch?v=PDpZpj2A3F4

Possibly, you could find this phrase of biblical inspiration proper for expressing at least some of what is felt in the uncovering of the type of truth your sentence evokes; I am talking of the celebrated "Let there be light", the motto of numerous institutions of higher learning. In this reference we find the following words.

• It’s just that, for the ultimate light to shine, a story must first unfold. So, our sages tell us, this light was hidden away for a time to come. Gradually we learn how to uncover that hidden light within each event, object and person that enters our lives.

How about the idiom dawn on? From The Free Dictionary:

dawn on: Become evident or understood, as in "It finally dawned on him that he was expected to call them," or "Around noon it dawned upon me that I had never eaten breakfast."

Your example:

It (finally) dawned on me that my mom's cooking was actually quite basic.