Don't expect to find your standard chicken tikka masala and bhaji recipes in Chetna Makan's new cookbook, because Chetna doesn't do the expected.

In her first cookbook, The Cardamom Trail, the 2014 Great British Bake Off contestant explored how to use Indian spices in baking, and now her second recipe collection, Chai, Chaat & Chutney, takes an even more interesting tack.

Packed with fresh, fast street food, it's crowded with dishes best eaten with your hands, straight from the fryer and in twisted paper cones; dishes that Chetna couldn't get enough of while munching her way around India for research.

"After The Cardamom Trail, I wanted to do something which is more my passion and my growing up; that showed a bit of where I come from," she explains. "People think Indian street food is limited to the three or four dishes that we all hear about, like panipuri [hollow, deep fried crispy dough filled with sour, spicy water], and I wanted to show there's so much more."

But with a country the size of India, which has a sprawling population of more than 1.3 billion, and all of those people eating, cooking, trawling markets, frying fish and snacking on street corners - how do you go about distilling such an incredible cacophony of foodie goodness?

"I actually didn't know where to start because there's so much," admits Chetna, who lives in Broadstairs, Kent with her husband and two children. "It's a massive country - different cuisine everywhere - so I thought, 'OK, I'm just going to pick the four big cities and focus on that'."

The big four - Mumbai, Chennai, Delhi and Kolkata - she explains, each have their own signature foods and flavours. Mumbai "is a very metropolitan city, so takes food from everywhere in the country, but it's got its own really distinctive dishes, like vada pav [deep fried potato balls] and dabeli [spiced potato and chutney wedged in a bread roll]". Chennai is "very big on South Indian food, there's lots of coconut, lentils, rice, and the typical dosas [savoury pancakes]". In Delhi, people "eat very heavy, they really specialise in flatbreads", while in Kolkata you can expect "lots of fish".

Chetna studied fashion design in Mumbai before moving to the UK in 2003, so aside from noticing a surge in Chinese influenced dishes, the food she encountered on her return wasn't "such a surprise".

"I was like, 'That tastes delicious, yeah, yeah, yeah, I've eaten that hundreds of times', but in Kolkata it was like, 'Oh my God, this is amazing'."

She'd only been to Kolkata, which sits on the Bay of Bengal in East India, when she was tiny, and couldn't remember anything she'd eaten on that childhood trip, but this time around, she went big on rice and lentils topped with crispy slivers of fried fish. "It's my favourite chapter in the book - I absolutely loved the food."

What all four cities do have in common though, is how kaleidoscopic their street food stalls and markets are compared to Britain's.

"They're very, very different," says Chetna with a laugh. "There's more colour and life, it's all haphazard. Here [in the UK], the street food stalls you go to are so organised! Everything is like clockwork - everything's in separate bowls! But there, oh!"

"I went to Kolkata and the first day there I went out, it was pouring - I went in monsoon season. There was this couple and they had this bright blue plastic sheet which was covering their stall," she remembers breathlessly. "There was water pouring from the side, and it was literally stood next to a big electric board! And then, in front of that, in the rain, they had this massive pot and this coal barbecue all lit up to fry the puri, and I'm thinking, 'Oh my God, you're right next to the electric board and it's pouring!'

"But it was the most amazing puri. They were just setting up and they had rice, daal and they were frying fish fresh, absolutely fresh, oh, it was so good - but shocking! Everything is haphazard, it's not organised at all."

There is beauty in the technicolour chaos though, she says. "It is more inventive, that's the fun of it. It's so colourful - even the cooking pots are covered in flowers!"

Chetna started cooking as a child, following her mum around the kitchen, helping to chop and stir, before confecting birthday cakes for her own children got her addicted to baking. She's decided she'll definitely give the new Bake Off on Channel 4 "a go" but admits, "If I don't like it, I won't continue".

Straight-talking, to a point just shy of blunt, Chetna's counsel for this year's baking hopefuls is: "You have to find your strengths and stick with it, that's my only advice. That's what I did. I didn't think I had to do things a certain way, or think, 'I have to do this traditional English thing', I knew my spices, I knew my stuff and I just stuck with that."

And it's certainly paid off.

FISH CHOPS

Ingredients

(Makes 15)

3 large eggs

300g skinless cod fillets

1 onion, finely chopped

Handful of fresh coriander leaves, finely chopped

2 garlic cloves, finely chopped

2 small green chillies, finely chopped

1/2tsp salt

Sunflower oil, for deep-frying

Sea salt flakes

For the coating:

2 eggs, lightly beaten

100g golden breadcrumbs

Method

1 Put the large eggs into a small saucepan, cover with water and boil for 10 minutes. Drain and leave to cool, then shell the eggs and mash them in a bowl.

2 In a food processor, blitz the cod to a coarse paste. Add the fish to the mashed eggs, along with the onion, coriander, garlic, chillies and salt. Mix thoroughly so the flavours are well combined.

3 Shape the mixture into 15 balls about the size of a lemon, then press to flatten them slightly. Dip each one in the beaten egg, then roll them in the breadcrumbs until fully coated.

4 Heat enough oil for deepfrying in a deep-fat fryer or heavy saucepan (ensuring the pan is no more than one-third full) to 170-180°C. Line a plate with some kitchen paper. Fry the chops a few at a time for about two minutes, until they are cooked through and golden. Transfer to the paper-lined plate and leave to drain excess oil while you fry the remaining chops.

5 Season with sea salt flakes and serve warm with your choice of sauce or chutney.

CRISPY SNACKS

Ingredients

(Makes 50-60)

60g split chickpeas (chana dal - available from Sainsbury's)

125g rice flour

125g plain flour

1tsp salt

1/2 tsp chilli powder

10 curry leaves, finely chopped

About 120ml water

Sunflower oil, for deep-frying

Sea salt flakes

Chutney of your choice, to serve (optional)

Method

1. Put the split chickpeas into a bowl, cover with water and leave to soak for one hour. Drain the split chickpeas, then grind them to a rough paste using a food processor, adding one tablespoon of water if necessary to achieve a rough, thick paste that isn't too runny.

2. Put the ground chickpeas, the rice four, plain flour, salt, chilli powder and curry leaves into a large bowl and mix well. Very gradually mix in just enough of the measured water (or a little more, if necessary), a few drops at a time, to bring the mixture together into a soft dough. Cover the bowl with cling film and leave to rest for 30 minutes.

3 Fill a deep-fat fryer or large saucepan with enough sunflower oil to deep-fry the papdi (ensuring the pan is no more than one-third full) and heat it to 190°C. Line a plate with some kitchen paper.

4 Take small portions of the dough, roughly the size of a grape, and roll them into thin discs with a diameter of 5cm. Working in batches, fry the papdi for two to three minutes, until golden brown. Remove with a slotted spoon and transfer the papdi to the paper-lined plate to drain excess oil while you fry the remaining dough.

5 Leave to cool, then season with sea salt flakes and serve with the chutney of your choice.

PARTY CANAPE

Ingredients

(Makes 15)

15 small fat green chillies

70g tamarind paste

1tsp carom seeds (available online or from Holland & Barrett)

100g gram (chickpea) flour

1/2tsp salt

Up to 120ml water

Sunflower oil, for deep-frying

Sea salt flakes

Method

1 With a sharp, pointed knife, slit the chillies lengthways along one side and remove the seeds and membranes.

2 Combine the tamarind paste and carom seeds in a small bowl and use this mixture to stuff each chilli. Set aside.

3 In another bowl, mix the gram flour and salt, then slowly add just enough of the measured water to make a runny batter.

4 Heat enough oil for deep-frying chillies in a deep-fat fryer or large saucepan (ensuring the pan is no more than one-third full) to 180°C. Line a couple of plates with some kitchen paper. Working in batches, dip each chilli in the batter, then carefully drop it into the hot oil and fry for about two minutes, until lightly coloured. Remove with a slotted spoon and transfer the chillies to a paper-lined plate to drain excess oil.

5 Once all the chillies have been fried, dip them once again into the batter and (again, working in batches), fry them a second time for two minutes, until golden brown and crispy. Transfer to a paper-lined plate to drain excess oil.

6 Season with sea salt flakes and serve hot.

Chai, Chaat & Chutney by Chetna Makan is published in hardback by Mitchell Beazley, priced £25. Photography Nahima Rothacker & Keith James. Available now