"I could whip up these dishes at home without having to pay between $12 and $18 for ambience and service," she says. But once or twice a month, there are weekends she feels she should treat herself.
The price of avocado toast in Singapore can range from $9.50 for the basics at Monument Lifestyle cafe in Duxton Road to $20 with a scoop of ricotta at The LoKal in Neil Road.
Mr Gurner is not the first to pick on the pricey superfruit. Australian demographer Bernard Salt likewise highlighted avocado toast last year as a symbol of millennial decadence.
Their critiques have even kicked off a new, ironic food trend, the avolatte - coffee served inside a hollowed-out avocado skin - which has since gone viral, to the delight of hipsters and the dismay of everyone else.
But there are millennials, such as musician Salima Nadira, who fail to see themselves in Mr Gurner's words. "Life is a constant hustle," says the 27-year-old, who also freelances as a videographer, model and baker. "I'm spending what I did in junior college. If I dye my hair, I'd rather do it at home than in a salon because it's just not worth it."
Lawyer Ervin Tan, 27, says Mr Gurner's argument represents "the same pernicious thinking behind judging refugees for owning smartphones".
"It fails to acknowledge that the cost of certain things - housing, for example - is so high as to exceed what mere frugality can achieve. It also ignores systemic inequality, which is a lot less easy or convenient to address than bluntly bashing millennials' brunching habits."
Most millennials readily admit their generation spends more than their parents did. For instance, civil servant Ou Ningfei, 26, spends up to $1,200 a month on food and drinks. "I buy rounds for my friends and, sometimes, they forget to pay me back," he says. "It just keeps adding up."
Agency writer Bryan Lim, 25, says: "I see people on my Facebook feed who are always travelling to expensive locations. I wonder if five years down the road, they're going to be troubled at how much it costs to hold a wedding banquet or rising milk powder prices."
Consumer culture and lifestyles have evolved, say millennials. They live in a world where e-commerce makes it easier to buy things than ever before; where they rely heavily on electronic devices built to become obsolete quickly; and where the experience, not the endgame, is king. After all, #youonlyliveonce.
"Millennials are more into novelty than the fulfilment of a particular need," says senior accounts executive Imran Khan, 28.
Business intelligence executive Marliyana Amir, 26, adds: "We're not aspiring to be millionaires like Mr Gurner. We are more interested in travelling the world and having experiences."
But although spending power has increased in absolute terms, so has the cost of living. Digital marketing executive Terry Pang, 26, says: "The generation before ours may have earned $2,000 a month to our $3,000, but they may also have paid $20,000 to $30,000 for a housing deposit, compared with $40,000 to $50,000 today."
Young professionals today are also faced with poorer work-life balance and a tightening job market, says researcher Christine Sim, 28. "Millennials are definitely working much longer hours than their parents did. There seems to be no such thing as switching off or disconnecting."
In such an environment, some argue that the line between frivolity and necessity grows blurry.
Retail manager Herman Shah, 29, will shell out $250 for facial toner, but considers it relevant to his work. "In this day and age, we are normally judged on our appearance. Since I deal with customers on a daily basis, it has become even more important as I age to look spot-on."
For others, splurging on life's little joys is what keeps them going.
Every two months, sales and marketing executive Peter Lim, 28, pays $56.50 for a bowl of quality negitoro don (chopped fatty tuna on rice). "The sheer amount of utility I derive from that bowl of tuna goodness reminds me why it is good to be alive."
National University of Singapore business administration student Brian Chua, 21, says: "I believe that money should always be spent where the mouth is and money spent on food is always worth it."
Mr Yeow Jianhao, 27, who works in sales at a technology company, spends 10 to 15 per cent of his take-home pay on eating out with family, friends and colleagues.
"Good dinners about once a week are, in my opinion, necessary to give back to the people who've supported you to make you who you are," he says.
"Money is a means to an end. So as long as we know why we are spending on something, why not?"
• The Sunday Times paid for the meals at Shop Wonderland pictured.
