What was the most surprising thing you learned while filming The Hospital: In the Deep End?

That I didn’t faint while watching brain surgery. The production team expected I would keel over like a giant redwood in a forest. Actually, I was so fixated by watching what was going on – did you know the brain actually does pulsate? And they’re cutting bits out and it’s like, “What’s that? What does that do? You just cut out an oyster-sized bit of brain – what do you mean, you won’t notice that’s gone?” And you can actually see the brainstem! Now, the brainstem is where it is at; you don’t fuck around with the brainstem. And you’re literally standing there, wide-eyed, looking at it through a hole. You feel like you are in amongst the pulsing fibres of the human noggin.

The fact I could talk to that patient the day after I’ve seen his brainstem was bamboozling. That kid has now been seizure free for over six months, so it is a brilliant, life-changing outcome.

I don’t have a prostate, but when I watched you watching a prostate removal I started holding my stomach for some reason.

Ha! The robot surgery stuff is interesting. My personal feeling about that is, the mere fact that so few men still monitor their prostate-specific antigen (PSA) levels – come on guys. I don’t understand why Australian men are so particularly bad at actually paying attention, to avoid that kind of stuff. Hopefully if they see that moment in the show, they’ll go, “Maybe I should have an annual blood test to see how my cholesterol is travelling, my blood sugar, blood pressure, PSA, iron levels” – so you can take action if things are drifting in the wrong direction. So you don’t turn up at the hospital going, “I feel a bit sick” and suddenly the hospital’s dealing with a stage-four cancer.

Women are sensible about going to have scans and tests. Men, not so much. I just think men have to grow up a bit.

Where is the strangest place you’ve been recognised?

While washing an elephant at an elephant sanctuary in Sri Lanka, by a group of very hairy-shouldered Bulgarian men who only spoke Bulgarian. And I heard [murmurs in vague Bulgarian with “judge” and “MasterChef” thrown in]. That’s a beautiful thing about that show, it had a very warm and positive reaction from people in all different walks of life. It’s a real privilege to be stopped by people to discuss food in Bangladesh or Stockholm or Madrid or Naples. It’s the nicest thing because it’s not really celebrity, it’s a familiarity.

But I’ll steal their recipe for their mum’s favourite fish dish. I always get something out of it!

What is the best meal you’ve had in Australia for under $20?

There’s a favourite Vietnamese place I go to near Prahran Market in Melbourne called Dad Restaurant that does a really good bún chả. I’m always happy with a burger from Andrew’s Hamburgers in Albert Park, mainly because of the genius idea they had where they shred a little white cabbage in with the iceberg lettuce so it is extra crunchy. I like under $20. I spend my life travelling around the world looking for great cheap food.

What’s your favourite restaurant in the world?

It’s not the restaurant, it’s the people you’re with. Full stop. Going with a couple of people you love to a cheap biryani place in Hyderabad and having biryani and marag, which is this amazing yoghurt and coriander soup that makes you go weak in the knees and makes your eyes water; it’s so delicious and so unexpected. Now, that’s not the best restaurant in the world by any stretch of the imagination, but it is, because of who you’re sharing the meal with.

When my son was studying in Europe, we went to this very good, very cool Madrid restaurant in an old butcher’s shop. It was delicious, we had crispy artichokes. That was pretty special. But that’s because I had the privilege of having quiet, uninterrupted access to my middle son for four hours.

I was away travelling 38 weeks out of 52 last year and I can tell you right now the best meal I have ever had is that roast chicken that the woman I love makes me when I come home. That is better than any restaurant meal.

What are you secretly really good at?

YES!! I love this one, I saw this in your Damian Lewis one and I wanted you to ask it, because I’ve got a couple. My secret skill is hiding alcohol in cocktails. Seriously, I’m a master. I can make the most innocuous tasting cocktail that’s properly boozy. I love making cocktails. I love playing with flavours. At the moment I’m making a bourbon and cherry sour. I’ll say one shot – I don’t think it was, it was three – but one shot of bourbon, one shot of a black sour cherry liqueur, juice of half a lemon, and some of that Wonderfoam stuff, or aquafaba. Do a soft shake with no ice, then shake it with ice, pour it into a coupe glass and serve. A dream combination.

And I’m famous for my dirty negroni – it is a negroni, with five mils of green olive brine. The saltiness of the brine makes the negroni sessionable. You’ll keep just having one more.

‘[MasterChef Australia] had a very warm and positive reaction from people in all different walks of life’: Gary Mehigan, George Calombaris and Matt Preston in their judging days. Photograph: Endemol Shine International

How many cravats do you actually own and do people give them to you all the time?

I don’t own nearly as many. I left a lot of them behind at MasterChef. I’ve probably got about 100. I’ve decided to go down the neckerchief route – it is a little less stated, not the full cowboy look. People do like to see something around my neck – they feel cheated otherwise, like I’m some sort of fake Matt Preston.

The embarrassing thing is not the number of cravats, because they’re just offcuts from fabric shops, they’re nothing fancy. The problem is probably the 28 pairs of RM Williams and the 100 suits. I have to rotate them into the attic – a box comes out and another box comes in. You want to have the perfect outfit, don’t you?

I did once work with a guy who had the same black suit and the same white shirt from Comme des Garçons, and that’s all he ever wore. He always looked very schmick, but that’s not me.

What is the best piece of advice you’ve ever received?

[Spy turned author of The Day of the Jackal] Frederick Forsyth once came to my school as the guest speaker at a dinner. I got to sit next to him on one side and on the other side was the head boy, who was the most boring boy in school. So Forsyth just talked to me for the whole evening. It was fantastic. The most unbelievable experience. And the last bit of advice he gave me is: listen, because opportunity knocks quietly. He said, “If you’re not listening, you’ll never know where that surprising big break will come from. If you’re talking the whole time, you won’t hear it.”

What has been your most cringeworthy run-in with a celebrity?

The lead singer of the Whitlams is called Tim Freedman and the lead singer of You Am I is Tim Rogers. And I once went, “Tim Rogers!” at Tim Freedman’s face.

I’m sure he was convinced that I was doing it on purpose. I wasn’t! I think the Whitlams are pretty freaking cool. But the way he reacted made me think that maybe he was always the slightly uncool Tim. Because Tim Rogers is super cool, right? We can all agree on that. And the Whitlams are wonderful. But wouldn’t you always be going, “Am I the second-coolest kid? The least cool Tim from 90s Australian rock?” That was really bad.

If you had a sandwich named after you, what would be in it?

That’s a big question.

I like that this is the one that’s got the most serious response.

Is the filling representing the person, or is it just about a really good sandwich?

A lot of people just go for the sandwich that they love the most.

I once took a job on a TV show because I wanted to go to Mozambique to eat a Prego roll, which came from Portugal originally. It is the best steak sandwich in the world. And I would like to be the best steak sandwich in the world. It’s very simple. It’s garlic butter, rocket and delicious steak which is seared but super tender. The roll is crusty but the crumb is open enough to suck up the garlic butter and the juices of the steak.

It’s taken me three visits to Portugal and one to Mozambique to now be able to make that roll, and I would like to be remembered as one. To be able to say, “I’m in the little village of Prego in southern Portugal and I’ve made a friend a Prego roll as good as one I can get here” – that’s when you know my time here is done. I can step back into the shadows.

Matt Preston, Jelena Dokic and Ruby Rose are the three participants on season two of The Hospital: In The Deep End, which is airing on SBS and SBS on Demand now.