It does. The idea for this sentence came from a show I watched about milk. The cows did end up eating onions one day and yes, the milk tasted like onion...
It seems strange that the same word for cows is also the same word for fruits, unless I have it written down wrong. The lessons said that פירות or פרות can be used for fruit (pl), but cows are also פרות? Are they pronounced differently?
In order to avoid confusion you'd almost always write fruit as פירות. They're indeed pronounced differently, perot = fruit and parot = cows.
in order to avoid this, פירות became a common form, yet it is wrong and should be פרות; although it should be noted that in full spelling (with niqqud) fruits is פֵּרוֹת while cows is פָּרוֹת
Arent ות and ים different gendered plurals? Or is it ok for onions to be male plural since it is not the verb for cows (female plural)
No. There are letters that appear in all the words from the same root, but there are also a certain number of letters that appear for different reasons. One of the things that affects the form of the word (or rather the verb) is the בניין that they belong to. It is just like the ing suffix in En (when one cook he\she is מבשל/ת, when one sit down he\she is מתיישב/ת etc.). You can read abot the בניינים here: https://en.wikipedia.org/wiki/Modern_Hebrew_verb_conjugation. Other things that affects the form of the word - although differently - are "the use letters" - אותיות השימוש which are מש"ה כל"ב (they indicate location, time, purpose, known label, question label, linking etc.), אותיות אית"ן, these letters come before a future verb to indicate the person (1st, 2nd or 3rd, single or multiple, masculine or feminine - אני אשב, אנחנו נשב. את תשבי, אתן תשבנה, אתה תשב, אתם תשבו, הם ישבו הן תשבנה etc), אותיות תמיהו"ן these letters come after a past verb to indicate the person (אני ישבתי, אנחנו ישבנו, את ישבת, אתן ישבתן, אתה ישבת אתם ישבתם, היא ישבה, הן ישבו, הוא ישב הם ישבו etc) and אותיות הכנוי"ם, these letters are used to mark the person in the different forms of the wors (hand - יד, my hand - ידי, your hand - ידך, his hand - ידו etc.)
I think he meant whether לבשל (to cook) and בצל (onion) have the same origin/root. The answer is, as far as I know, no. Also, notice that לבשל is with ש rather than צ.
I know that that's what she (or that it just coincidence that g1r1 so similar to girl?) meant, I just... well carried away with all sorts of things that affect words form