Need an urgent advice on subject verb agreement, thanks teachers. ^^

[Help Wanted]

Dear teachers,

I was wondering if I should use "is called" or "are called" in the following blank. Please explain to me too.Thanks soooooo much for advising.

Cooked rice in bamboo leaves ___________ rice dumplings.

[Casiopea]

"cooked" is an adjective and "in bamboo leaves" is a prepositional phrase. Neither can function as a subject, so neither agrees in number with the verb. Only subjects agree in number with the verb. Subjects are nouns.

EX: Rice is called ...

[Casiopea]

That is, "Cooked rice is called ... ."

[Help Wanted]

Thanks for your advice, teacher Casiopea.

So, how can I rephrase the sentence if I need to use "is called"? Should I omit the "s" in rice dumplings? Please advice, thanks again.

[Casiopea]

Bamboo leaves filled with rice are called rice dumplings.
Cooked rice balls in bamboo leaves are called rice dumplings.

[Help Wanted]

Thank you soooo much for rephrasing the sentence for me. All the best, itsgoobie ^^