The celebrity chef shows us where to eat in the Melbourne suburb he knows best.

​Springvale is only half an hour south-east of central Melbourne, but it feels like another city. With nearly 21 per cent of the suburb's residents born in Vietnam, and the parents of more than 84 per cent born overseas, it's the Victorian mecca for Vietnamese food lovers.

I'm sitting outside no-frills Cafe Dai Gia with Khanh Ong, two-time MasterChef contestant, cookbook author and co-owner of The George on Collins. Customers are sitting around us sipping ca phe sua da (iced coffee with sweetened condensed milk).

Ong's dressed in all black, from his hair to his leather pants tucked into calf-height boots, brightened by a T-shirt sporting the slogan "you are loved", which he sells online to raise money for Minus18, a LGBTQI youth charity. Ong visits Springvale every Monday to buy groceries and see his mum, Dzung Chau, for dinner.

"I was born in a refugee camp in Indonesia, but we moved over here when I was two. I've pretty much been in Springvale my entire life," he says.

Ong is topping up my half-finished iced coffee with oolong tea from an insulated jug ("it's what they do, don't ask me why") when I spot Chau crossing the road. She looks more like his sister in her slim jeans and pointed heels, but the foil tray of hot nem nuong fermented pork sausages and fried chicken ribs she is carrying scream "Vietnamese mum".

She's also brought her signature nem chua, a garlicky, raw pork sausage that ferments for three days before it hits the display at her butcher shop, Tam's Asian Butcher. We head around the corner to Springvale Central to share the leftovers with Chau's staff. Ong stops abruptly at a produce display in the middle of the mall.

"Oh my god, bon bons!" he says, "You almost never see these!"

At Thanh Tien, where Ong buys his groceries, I try bon bons for the first time: the tropical fruit tastes like lychees, looks like tiny potatoes and grows in grape-like bunches. We walk into his mum's shop opposite and I notice a framed photo of Ong in a MasterChef apron and a section dedicated to whole organs that you just don't see at Melbourne's "big three" markets. The butcher is named after Ong's father, who the family lost to cancer when Ong was in year 10.

"Mum and dad opened their first shop when I was in year two," says Ong. "The community loves the fact she took over dad's businesses when he passed away; there's a woman in charge and there's this respect for her."

Ong shrugs when I ask how many shops Chau leases out, but says there are at least five in Springvale Central alone. Across the way is Saigon Fresh, where he gives me an animated rundown of the instant noodle section ("pack the versatile tom yum Mama brand with Asian herbs and serve with sliced beef or poached prawns").

There's also a stand-alone kiosk nearby called I Love Banh La. Later, I'll buy banh bo nuong (green pandan honeycomb cake); banh duc ngot (pandan rice cake) and xoi vo (sticky rice with mung bean) to take to my parents' house for dinner.

But first, lunch. Ong and his mum don't always agree on where to eat. Chau loves Vinh Dat for barbecue duck and pork, but Ong prefers Golden Chopstix.

Here, he orders a platter of three roasts with rice or noodles for lunch, but the family will also buy a whole roast duck ($30) or barbecued pork ($32 per kilogram) to eat together at home. Ong thinks his mum prefers Vinh Dat because it's near Huy Anh Bakery, a small shop that makes her favourite banh kep, a $2 coconut waffle shaped like a flower.

They're united when it comes to pho – their favourite is at Pho Hung Vuong – while Nam Giao's lemongrass-loaded bun bo hue (spicy beef noodle soup from central Vietnam) is another joint favourite.

This is Ong's preferred Vietnamese noodle soup, while Chau can't go past southern Vietnam's bun mam, a pungent, fermented seafood soup with rice noodles that she orders at Bun Ngon. Here, we also try mi quang from Quang Nam in central Vietnam, recognised for its turmeric-dyed noodles.

"I feel like the food in central Vietnam gets lost," says Ong at the table. "When places are known for one thing, that becomes the thing. Bun bo hue is the thing; no one cares about its sisters and brothers."

On the way out, the owner's daughter gushes while asking for a selfie with her favourite MasterChef contestant.

Our next stop is Quan Lua, which specialises in grilled pork bought wholesale from Tam's.

I leave the ordering to the pros. Bun thit nuong lands first, a bowl of rice vermicelli with de-skewered grilled pork, chopped spring rolls, peanuts, cucumber and a forest of Asian herbs that Ong dresses in nuoc mam fish sauce and tosses like salad.

There's bun cha, smoky chunks of pork and meatballs with pickles in a broth-like sauce, plus vermicelli and herbs for dipping.

My favourite dish is what Ong calls a "worker's lunch": sweet, lean pork chop on crumbly broken rice accompanied by a fried egg, pork loaf, pickled carrot and shredded pork skin.

Chau's phone rings and she excuses herself to get back to work, leaving Ong and I to settle a final disagreement: Springvale's best banh mi.

We walk up to Springvale Road where Bun Bun Bakery and Tabac Bakery are 50 metres apart. There's a queue outside Bun Bun, Chau's pick, but when I see trays of tiger loaves coming out of the oven at Tabac, my banh mi sense starts tingling also.

The bread is perfect; a brittle crust that carries an obscene amount of chopped crackling pork belly, fresh salad and swathes of sweet yellow mayonnaise and pate.

Could this be the best banh mi in Melbourne?

Need to know

• Cafe Dai Gia, 1A Windsor Avenue, Springvale
• Tam's Asian Butcher, Thanh Tien, Saigon Fresh and I Love Banh La, inside Springvale Central, 268-274 Springvale Road, Springvale
• Vinh Dat, 15/9 Balmoral Avenue, Springvale
• Golden Chopstix, 2-3/60 Buckingham Avenue, Springvale
• Huy Anh Bakery, 1/17 Balmoral Avenue, Springvale
• Pho Hung Vuong, 2/15 Balmoral Avenue, Springvale
• Nam Giao, 3/218-220 Springvale Road, Springvale
• Bun Ngon, 266A Springvale Road, Springvale
• Quan Lua, 39 Buckingham Avenue, Springvale
• Bun Bun Bakery, 1/288 Springvale Road, Springvale
• Tabac Bakery, 296 Springvale Road, Springvale

Correction: An earlier version of this article identified the banh mi images as being from Bun Bun Bakery. This has been updated to Tabac Bakery.