When Walt Bettinger, chief executive of Charles Schwab, is thinking about hiring someone, he invites them out to breakfast. He arrives early, takes the waiter to one side, hands over a large tip and tells him to mess up his guest's order. He then sits back and watches the candidate's response.

"That will help me understand how they deal with adversity," he recently told the New York Times. "Are they upset, are they frustrated or are they understanding? Life is like that, and business is like that. It's just another way to get a look inside their heart rather than their head."

As he doesn’t reveal his favoured response to getting scrambled eggs when you’ve asked for poached, I’ve been trying to work it out for myself. When candidates greet the screw-up with silence, does that make them craven wimps? Or could it suggest they are pragmatic and care more about landing the right job than the right breakfast?

Then again, maybe the scrambled eggs looked so good, they decided they never really wanted poached ones anyway?

While this test is a rotten way of looking inside the hearts of job candidates, it does offer a glimpse into Mr Bettinger’s own. Not only is his trick in bad faith, it is at odds with Charles Schwab’s business model — based on honesty and transparency. To practise it is a bit off, but to boast about it is insane.

Any CEO who tells journalists he has found the interview silver bullet is talking nonsense, as there is no such thing. There was Mark Zuckerberg recently insisting that he only hires people he would like to have as his boss. This sounds delightfully humble coming from the 31-year-old tycoon, but I don't believe it for a moment.

Facebook employs 13,000 people, and if Mr Zuckerberg would be happy to work for every one of them, that makes him worryingly undiscerning. Even if I believed him, his test is not a good way of hiring. A company in which everyone wants to be a chief is not going to work.

Still, there was one part of Mr Bettinger’s approach that was spot on. That is to invite candidates to a restaurant — although he picked the wrong meal. Breakfast is too early and too uncongenial: lunch is the one to go for.

For the past 20 years I have been interviewing people in restaurants. For the same amount of time I’ve been doing straight interviews minus the lunch, and I can confirm that the first is invariably a better way of doing it.

That is partly for the circumstantial clues a meal provides. Is the person nice to the waiter? What do they order? Are they decisive? Greedy? Can they manage a knife and fork?

More than that, what lunch has going for it is that it demands small talk, which is a much better way of getting to know someone than big talk. The big talk of the normal interview has a serious flaw: it can easily be gamed.

The standard questions about strengths and weaknesses — as well as the pseudo clever ones asked at Goldman Sachs about getting out of a blender if you found yourself the size of a pencil — all lend themselves to pat answers.

Even the supposedly revealing question favoured by Miranda Kalinowski, head of hiring at Facebook — "On your very best day at work, what did you do?" — offers plenty of scope for pretending to be someone you are not.

Were I asked this, I’d keep quiet about the great day I had recently which involved a long gossipy lunch with a colleague, lots of praise and precious little work. Instead I’d fabricate a day during which I came up with a genius idea, and slogged away to find a way of making it happen.

Small talk, by contrast, can’t be gamed, because it seems too small and random to bother about. Yet through this meandering and incidental chat we often get a better glimpse of a person — in both mind and heart.

When I interviewed the writer Jonathan Franzen recently, I asked him big questions to which I got predictable big answers. But when we started talking about DIY he let slip that he had just painted a room in his house himself because he can't bear paying people to work for him — and that he wasn't satisfied until he'd applied four coats of paint.

Above all, there is something about the curious business of chewing and swallowing together that is levelling; it is easier to work out if you like someone when eating than when eyeball to eyeball in an interview room.

I’m not suggesting that all you need to get the right person into a job is to break bread with them. Hiring is hard — the evidence suggests that companies that do it more thoroughly tend to make better choices. All I’m saying is that at the end of the process, lunch should be the final course.

- Copyright The Financial Times Limited 2016.