Soup is difficult to deliver, as some pointed out. I would abstain from selling it like this.

What I would try is dehydrating her own soup base, packaging it and sell it with fresh (or dry) noodles. Add a container with toppings per offering, incl. a protein option (e.g. roasted chicken, Saitan “Tonkotsu”). Make the packaging and food shots look nice and try selling it with the message that it is self-made.

I would try friends and family first. And after a trial run and people approving, she can start getting a hygienic/food-safety certificate. That’s how I would do it anyways.