While most residents in the posh enclave of River Valley are fast asleep at 4am on a Friday, a small corner of the neighbourhood is wide awake and bustling.

Late-night eatery Spize in River Valley Road is where one can find a convergence of all sorts of people, no matter the time.

From families in shorts and slippers who are up way past their bedtime to glammed-up youngsters rounding up a night of partying, these people have only one thing on their minds: supper-and a quintessentially good Singaporean supper at that.

After more than a decade at 409 River Valley Road, Spize has unmistakably become a supper landmark - the sort that taxi drivers know how to get to without needing an address.

Together with the chain's second outlet in Simpang Bedok, the Spize brand has become synonymous with late-night meals, thanks largely to its long hours of operation-starting at noon and shuttering only at 6am on weekends.

But there is more to the brand than just 18-hour days. The real secret to its success is its option galore, jam-packed menu, offering everything from 17 variations of prata and nasi goreng to kebabs, pastas, steaks, hotplate barbecue and burgers.

For the two brothers behind Spize, it is the nostalgia of taking the brand from coffee shop to restaurant chain that they are particularly proud of.

Mr Anil Sabnani, 41, founder and managing director of Spize, who co-owns the chain with his younger brother Haresh, says: "The huge menu we offer is definitely pretty unparallelled. But for our patrons, it's the memories from those many late-night suppers that have helped turn them into loyal customers. Food is what people love, but nostalgia is what keeps them coming back."

For a chain so proud of its nostalgic heritage, it is interesting to note that neither River Valley nor Simpang Bedok - its best known locations today - were the original venues for Spize Cafe when it first opened in 1997.

The brainchild of Anil, the first 600 sq ft Spize cafe opened at Shaw Towers in Beach Road and offered a Western menu of sandwiches, pasta, desserts and coffee.

"The year 1997 was before the coffee craze kicked in… It was pre- Starbucks days, without the cafe culture we see today. Back then, we were one of the few places offering casual food and coffee till midnight daily, which is why things took off almost immediately," he recalls.

Only 23 then, his decision to open his own restaurant was a gutsy one, but not one that he did without paying his dues.

Describing himself as someone who was "too savvy for school", the father of a seven-month-old daughter studied commerce at St Patrick's School, but began working early- taking on jobs in the food and beverage and hospitality sectors as soon as he was 16. His wife is the human resource manager for Spize.

"I did everything from room service at hotels to banqueting and managing restaurants.

"By the time I was 19, I was managing a restaurant, helping the management set up a new venture and regularly roping in Haresh, who is three years younger, when I needed part-time help," he says.

Bold, big dreams for Spize

The sons of a High Street sari salesman and a mother with a home tailoring business, the two brothers grew up in the east coast of Singapore and admit off-the-bat that their less-than-affluent upbringing encouraged them to become financially independent from a young age.

"We didn't have a lot of money, but we grew up watching the entrepreneurial spirit that our parents had," says Haresh, 38, who is also a Spize managing director and father to two daughters, aged 19 months and 1½ months.

He adds: "They didn't have a lot, but they always gave us the best that they could. It's what pushed us to start working as soon as we were able to get paying jobs."

For Anil, that meant working his way up in F&B and hospitality, with Haresh following in his footsteps.

Given their financial situation, they would have happily continued as employees if not for the family relocating from Bedok to Serangoon North when Anil was 23 and Haresh, 20.

The sale of their family's five- room HDB flat netted them $40,000 in profit, which their mother serendipitously left in her older son's hands.

"It was the capital I needed to start Spize Cafe and it's why Haresh and I are forever indebted to our mother," Anil says. "In fact, the name Spize is a dedication to her and to the wonderful smells that waft out of her kitchen."

Crafting a menu with help from his mother, books and television shows, the foodie turned his passion for F&B into dollars and cents - working full time as the cafe's chef and doing everything, from making sandwiches to flipping pastas, in the kitchen.

Haresh, a Temasek Polytechnic student at the time, was soon roped in to help as well, and with their mother helping to man the cash registers, they built up enough traffic to open a second, bigger outlet within two years, down the road at KeyPoint Building. They called it Spize Bistro.

Haresh recalls: "The long hours and steep learning curve were challenging, but because we were so invested and passionate about the business, we managed to stay afloat and do quite well."

Even though they closed Spize Cafe in 2000 to focus on Spize Bistro, luck was on their side and serendipity struck yet again in 2003 - prompting an unexpected move to their current location in River Valley Road.

It was while walking around the shophouses in River Valley area that the brothers were approached by a man who ran a prata shop at 409 River Valley Road. A shipping business owner, he told them he was looking for buyers to take over his father's prata restaurant and, to the surprise of the duo, proposed that they buy it over.

"We didn't even know him, we were strangers," Haresh says with a laugh. "He must've seen something in our eyes for him to make that offer. For some reason, we were crazy enough to jump at it too."

So just like that, with minimal renovations or fuss, they paid $70,000 and took over the prata joint - keeping the staff, chef and menu and simply rebranding the space to Spize. Over time, they consolidated items from Spize Bistro with the offerings from the prata restaurant's original menu - creating the diverse food selection available today.

In 2005, the brothers decided to close Spize Bistro to focus on Spize at River Valley. They also moved a Roti John stall that Haresh was running in Simpang Bedok across the street to a larger restaurant location and rebranded it Spize, offering the same menu as its River Valley outlet.

With a steady flow of customers streaming in day and night, the brothers could have easily sat back and coasted on their success. But innovation has always been the name of their game.

Their first forward-thinking move came in 2005 with the introduction of point-of-sale systems in their restaurants, centralising orders taken by servers and directing them automatically to the kitchen and beverage teams.

Haresh, who oversaw the project, says: "Back then, most prata shops operated the same way - with orders manually written on notepad paper and dropped off by servers at different parts of the kitchen. But I remember thinking, 'Why should we be like everyone else? We should set the bar.'"

The $50,000 point-of-sale systems led to more efficient service and fewer mistakes.

In 2009, Spize innovated again, introducing a food-delivery service. Seven years on, it offers an island- wide delivery service from its River Valley and Simpang Bedok outlets and has a dedicated call centre and an online portal for deliveries.

But perhaps the best example of the brothers' desire to keep Spize a step ahead of the competition can be seen in their decision to rebrand the look of the business in 2014 - complete with a new logo and fresh, modern interiors.

No longer the laid-back coffee shops they used to be, Spize restaurants now boast walls with murals, bold orange and black tiling and open-plan kitchens that give the space a Mediterranean-inspired flair.

It is no surprise then that Temasek Club, a recreational society for military personnel, approached the brand in 2013 when it was looking for a hip, halal eatery to draw a younger crowd to its new premises in Rifle Range Road.

For financial professional and long-time customer Gerard Tan, 44, the third and newest Spize outlet, which opened in October, is the chain's best one yet.

"I was worried that with the rebranding, prices would go up and the eatery I've been going to since my clubbing days would lose its charm," he says. "But it still has that wonderful menu and pocketfriendly prices despite the upgrade in the look and feel."

For Anil and Haresh, it is the joy of seeing these repeat customers that keeps them doing what they do.

Haresh says: "We've seen couples who were dating get married and, years later, bring their children to Spize. To be able to find this happy medium between staying fresh while celebrating nostalgia is the most important thing to us.

"We're just simple guys who went after a big dream. And at the end of the day, we just want to make food that makes people happy."

Haresh on Anil: My brother, my mentor

Younger brother Haresh Sabnani considers his older brother "a mentor".

Following Anil's footsteps closely even as a teenager, he recalls seeing his brother's work ethic in place from an early age.

"He never failed to help me - getting me part-time jobs wherever he worked and teaching me about everything from cooking in the kitchen to operating the business," Haresh says.

"Watching him made me want to prove my worth - like the time I convinced him to let me run our Roti John stall even though it meant working the graveyard shift till 4am every day."

And though the brothers admit they do not always see eye to eye, neither is the sort to fly into a rage when his idea is shot down.

"Out of 10 ideas that I have, usually seven are rubbish," Haresh quips with a laugh. "But when I realise my idea won't work, I don't tell Anil he is right. I just stop talking about it. My silence is my admission that his opinion was right."

After years of working long hours in the kitchen, Haresh says he now treasures whatever free time he has with his family.

"It can get tough, when you work together, to separate personal life from business," he says. "But now that both of us are fathers of young daughters, we've realised the importance of making and spending time together without talking about work. That has really helped us to relax and made us closer."

Anil on Haresh: He's creative, I'm detailed

Big brother Anil Sabnani sees his younger brother as the yin to his yang. "We complement each other completely," he says. "Haresh is creative and innovative and that helps balance my detail-oriented and micro-managing nature."

Haresh helps to oversee the River Valley and Rifle Range outlets while Anil manages the Simpang Bedok branch. But when it comes to responsibilities and decision- making, they are happy to put everything on the table.

"We tried to bring the management teams over from one branch to another, but noticed over time that it's best to let each branch operate independently," Anil says.

"Until 2011, we were still cooking in the kitchen, but now that we have taken on a more management role, splitting responsibility by location has worked best for us."

And though he agrees that for many years, he took the reins because he was the older of the two - including making big business decisions and setting the path the brand would take - he says he has tempered over time by letting Haresh take on more responsibilities and become an equal partner in the business.

"So many innovative decisions have been Haresh's and I am really proud of him for seeing through these ideas that have helped the business. He was the one to notice how point-of-sale systems were helping other F&B establishments and convinced me to change our operations. More recently, the set- up of our Rifle Range branch was overseen by him," Anil says.

"I've been happy to give him space to try new things and, now, I just guide him if he needs me. I know he has it in him to bring his ideas to life."

For the older brother, it seems that it is working and creating the Spize brand with family that he is most proud of.

"We may fight or disagree, but at the end of the day, we are able to keep it in the family and figure a way out," he says. "There's a comfort level there. It's a trust that cannot be replicated."