Matzo balls joke

There’s a story about Marilyn Monroe, having been fed matzo ball soup several times by her mother-in-law, asked “do you guys eat any other part of the matzo?”

Is this original with her or just a variation of an older joke? And if it was original with her, was she being witty or just ignorant of Jewish cuisine?

According to this, it was her playing up the blonde air-head image she was known for.

Marilyn apologised for the matzo-ball soup remark. She knew of course that a matzo, whatever it was (I hardly knew myself) was not an animal. All she was trying to do was to live up to her lovable airhead image, as carefully created by the studio.

Matzoh ball soup fellates with great alacrity.
Unfortunately, Mrs. Plant (v.3.0) likes it.