When Dr Rahul Mandal rose to fame on the ninth series of The Great British Bake Off, he quickly became a firm fan favourite – for his intricate bakes and sweet, self-deprecating nature.

The research scientist from India went on to win the show, but Mandal had only just started baking a few years previously – when he moved to Rotherham, South Yorkshire, in 2015, to combat the loneliness he felt not knowing anybody there.

“I used to go to the supermarket and the staff were very friendly, I could easily spend two hours there, buying a few things, speaking to the staff,” the 35-year-old remembers. “Then I started bringing cakes to them, and I started to have more friends in the supermarket and the leisure centre.

“In a strange way, I became close to a lot of them – without me realising, and without them realising, how much of a big role they were playing to support me emotionally.”

He remembers vividly a time when his parents left after visiting from India for two months. “I dropped them at the airport and after I came back, I felt very lonely – I couldn’t stay in the flat because suddenly, it was all empty again,” Mandal says.

So he went to the local supermarket for a couple of hours. “I actually felt a lot better when I came back home. I obviously missed my parents, but it wasn’t so much that I couldn’t even stay in the flat on my own. As human beings, we’re supposed to be socialised, we’re social creatures.

“Growing up, I never had a lot of friends, but I had a huge family around me. And in a strange way, the people in Rotherham kind of became part of myself.” It was these people who encouraged him to apply for Bake Off – and he’s still friends with them today.

Now Mandal – who works full time at the Nuclear Advanced Manufacturing Research Centre at the University of Sheffield (where he worked before GBBO) – is back with his debut cookbook, Showstopping Cakes.

The recipes are a culmination of five years of learning about cake, he says. From Bake Off favourite techniques like chocolate collars and fillings like crème diplomate, to recipes he’s made loved ones for special occasions – like the lemon and fennel fault line cake for colleague who was having a baby, and a cranberry, white chocolate and cardamon cake for a christening, as well as some bakes that would not look out of place at a wedding.

It’s taken a while, he admits, because winning the show was a “big shock” for the unassuming man from Kolkata, and it took him a long time to accept it.

“I am someone who literally came to the UK to do a PhD [in optical engineering] and after that I had a research position. I just used to go to the lab or go to the office, come home and maybe go to the gym or for a swim – that’s it!”

In India, Mandal says: “I grew up with home-cooked food, we never really went to restaurants, because my mum is a great cook and my dad used to go and get fresh vegetables and fresh fish, but we never had an oven so baking was never really a thing. For me, bread meant you buy bread from shops, I never knew that you can actually make a loaf of bread. Obviously, we had chapatis and pooris – because you don’t need an oven.

“I’ve never been a sporty person, I was never into watching cricket like most of my family, but I used to like cooking programmes. I’ve loved to see my mum cook and be around when she was cooking, learning how it was happening.

“But in my house, men can’t cook. My dad can’t cook, my uncle can’t cook, and I wouldn’t say I was discouraged – my mum wouldn’t mind – but I don’t think my dad ever encouraged it, because he thought I should have concentrated more on my studies.”

These days though, he’s keen not to typecast what a ‘baker’ looks like. “Let’s not put any gender stereotypes or even race stereotypes in baking – everyone loves eating right? It doesn’t matter what gender you were born, what sexuality [you are] or what race you are, most people like cake.”

Mandal arrived in the UK to go to Loughborough University in 2010 (“We used to store stuff in the oven”, he laughs, of his shared student house). But when he joined the university’s Garden Society, “A lecturer came with [homemade] breads, biscuits and cookies and I was shocked to see you don’t have to buy bread – you can actually make bread at home!”.

For Mandal, baking has become intertwined with happiness. “I like to surprise people by making cakes, say for a colleague’s birthday. When you bring a cake to them and they look at the cake and it makes them happy, in a strange way that makes me happy,” he says. “So I think this is a kind of chain reaction of happiness – when you see someone getting happy because you did something for them, it makes you feel really warm and full. I live on those emotions – I’m a very soppy person!”

It was his kindhearted, gentle nature that viewers fell in love with back in 2018. “I can’t thank Love Productions enough for letting me be who I am – you need to feel secure and safe if you’re spending so much time somewhere,” Mandal says, but without a social media account, he had no idea when Bake Off was on TV, never mind that the public had really warmed to him.

“My colleagues used to take snapshots of nice Twitter and Instagram comments and send them to me, but I got a bit terrified about people stopping me in the street.” After being papped getting off a bus, his colleagues made a rota to pick him up for work.

Paul Hollywood was terrifying in his own way too. “Oh my God, he never spoke to us. Even after [filming] he was very quiet. Prue [Leith] sometimes came to our benches to have a chit-chat after the challenges, but Paul always kept his distance. I was very, very intimidated by Paul.

“Paul became really nice just after the final results were announced and then suddenly very friendly. I was so surprised to see him actually laughing and chatting with all the other people who came to the final. I felt like, ‘Is this the same person who was so scary in the tent?’.”

Still, Hollywood was mightily impressed with Mandal from the get-go – giving him the first-ever handshake for a showstopper challenge when he made a double-tier cake with a chocolate collar.

So what makes a great showstopper? “First it has to taste good, then it has to look good,” Mandal says. “To look good there are different ways of decorating, there are different surfaces to decorate – you have the side surface and you have the top surface. A lot of people don’t put something on the side of the cake.”

And many of Mandal’s cakes aren’t as difficult as they look, he promises. “If you start doing it, you will realise not one is as hard as it seems. If I can do it at home, you will be able to do it as well.”

Showstopping Cakes by Rahul Mandal is published by Kyle Books, priced £26. Photography by Maja Smend. Available now.