Rahul Mandal (Photo: Facebook/ The Great British Bake Off)

Kolkata-born research scientist Rahul Mandal has been crowned the winner of the Great British Bake Off 2018.

He beat off stiff competition from finalists Ruby Bhogal and Kim-Joy Hewlett to win the crown on Tuesday (30) night.

Mandal secured his victory by winning the final challenge where he created an edible rock garden made from orange-flavoured green curd, cardamon diplomat and orange buttercream. The finale also saw him competing with others in a doughnut Signature Bake task and pitta bread Technical Challenge over an open fire.

The finale was filmed during the summer heatwave the UK experienced in June and July and Mandal watched the episode with his parents.

“I watched the final with my parents, who are over from India, and friends and colleagues,” the Guardian quoted Mandal as saying. “It was very emotional but it was lovely to have the people who have helped me throughout my Bake Off journey watch it with me.”

Rahul’s place in the top three had been embroiled in controversy. Last week, some viewers accused the scientist of cheating during the semi-finals when he was shown continuing to decorate his bakes even after hosts Sandi Toksvig and Noel Fielding had called time.

Toksvig, however, defended Mandal, calling him an “astonishing talent.”

Speaking about the semi-final incident, Sandi told Digital Spy: “What you see is what you get [with Rahul].

“He’s a really charming man with very little self-confidence and an astonishing talent.

“The others all have talent, Briony is talented, Ruby is talented, Kim-Joy is talented but at the end of the day, it’s that bake on that day. I’m sorry if there is a backlash.’

She added: ‘Everybody is doing their best. These are not telly people. These are people who have decided to put themselves forward to do something that they are passionate about. So, I would hate for there to be a backlash against anybody.”