Jasmine Dinh has been working in her parents' sandwich shop since she was in primary school. "I remember once I wanted to surprise my mum by catching the bus by myself from school to the shop," recalls Jasmine. "She then told me that I could catch the bus every day and come help her at the shop. Goodbye after-school playtime!"

The shop is the legendary Banh Mi Bay Ngo in Bankstown, although when it opened in 1988, it was first known as Jasmine's Ice Cream, then Jasmine's Takeaway.

"About two years ago I officially renamed it Banh Mi Bay Ngo, after my father," says Jasmine. Bay means seven in Vietnamese, and Jasmine's father was the seventh uncle in his family, so her parents were called Anh Bay Ngo (Uncle 7) and Chi Bay Ngo (Aunty 7).

I've been eating banh mi from Bay Ngo for a third of its lifetime (and coincidentally, a third of my lifetime, too). Having written some dozen or so "best sandwiches in Sydney" articles, I have favourite places to go for specific varieties of banh mi – my favourite pork roll is in Marrickville, my favourite chicken roll is in Cabramatta, for instance. But when it comes to the best banh mi all-rounder in Sydney, that title has to go to Bay Ngo.

Smack bang in the middle of Bankstown's Vietnamese area, Bay Ngo offers the widest variety of classic banh mi fillings, without succumbing to weird modern fusions. Along with the pork and chicken staple, you'll find options such as meatballs, barbecue pork, pork skin, fishcake and tuna. And you can (and should) add a freshly fried egg to any roll on the menu.

The hot chicken roll used to be my staple, but after seeing another customer adding a fried egg to their roll last year, I've been ordering barbecue pork and egg. On my recent visit I finally tried a fishcake banh mi, which might be my new favourite, featuring thin slices of salty fishcake, Bay Ngo's wonderfully rich pate and its excellent selection of vegetables, which includes thick slices of cucumber, pickled daikon and a brightly coloured mix of carrot, coriander and red onion.

Everything, including the mayo, pate and garlic fish sauce that gets dripped over each roll, is made in-house. Asked what her favourite banh mi is after eating them for 30 years and trying every possible combination, Jasmine plumps for barbecue pork and fried egg, which she likens to Vietnamese bacon and egg roll.

Like so many Vietnamese Australians, Jasmine's parents fled Vietnam after the war seeking asylum. Working in the shop from such a young age, Jasmine didn't always understand the hardships her parents faced. "My parents worked so hard to build a life for us and needed my help during that time," she recalls. "I love that I had that time with my parents at the shop."

Sadly, Jasmine's mother died 15 years ago and her father two years ago. Jasmine now co-owns the family business with her stepmother Co Van.

"Our business these days is about carrying on tradition and making my parents proud," says Jasmine. "They built a legacy which continues to support further generations of our family. Our business is well known within the wider community and that's something that warms our hearts. We take pride in everything we do because it's a labour of love."

The low-down

Banh Mi Bay Ngo

Must-order dish Barbecue pork roll with fried egg, $6

Why stop at just one? Try the other best banh mi in Sydney

Marrickville Pork Roll, 236 Illawarra Road, Marrickville

Sydney's most famous banh mi. There are multiple locations now but the original hole in the wall is still the best. If the three kinds of pork in their rolls aren't enough, ask them to add a meatball, too.

KK Bakery, shop 2, 85 John Street, Cabramatta

This small bakery in Cabramatta is where you'll find Sydney's best chicken banh mi. Chicken marylands are roasted in a sweet stock and shredded off the bone to order.

Hong Ha Bakery, 1151 Botany Road, Mascot

The rolls at this always-busy 30-year-old banh mi institution are worth lining up for, whether you go with a traditional pork or chicken, or get crazy with a schnitzel banh mi, loaded with grated carrot and chilli.