My MasterChef hell: Deborah Ross takes on cooking’s toughest challenge

It’s television’s toughest culinary challenge – and its motor-mouthed presenters, Gregg Wallace and John Torode, have proved a smash hit with viewers. But how would the cooking skills of our intrepid interviewer stand up to the MasterChef test?

OK, let's play a game of MasterChef word association.

Me first, as it was my idea, as always. (Seriously, it would be nice if you put some work in every now and then.) So, here goes: "MasterChef. BBC. John, the shouty one. Redcurrant jus. Gregg, the other shouty one. GOD, YOU'VE GOT SOME BIG FLAVOURS, BOY! Your time starts now. I'D HAPPILY STICK MY FACE IN THAT! Eighteen minutes left. Stuart, 29, stationery salesman. Winning would mean everything to me. FONDANT! Seven minutes left. LOVE THE BEEFY PUNCH OF THOSE MUSHROOMS! We have a really difficult decision ahead of us. OH, YES ... YES, YES! We're looking for a truly exceptional amateur cook. Time's up. COOKING DOESN'T GET TOUGHER THAN THIS..." Although, come on. Say you were in a collapsing mineshaft, with leprosy, and your nose was falling off, and a toe, and a knee, yet you still had to rustle up a restaurant-standard meal that displayed flair, coherence, an understanding of (BIG!) flavours and spot-on seasoning? That would be tougher, surely. Sometimes, I don't think Gregg, the shouty one, and John, the other shouty one, even know what they are getting all shouty about.

But we shall see. We shall see because today – yes, this day, right now, because I have to do everything around here – I am off to MasterChef, to cook for The Shouty Ones. I am not thrilled about it. I do not think it will be fun. I just hope it won't be humiliating, although I'm well used to humiliation. I once baked a cake for my son's birthday without noticing the flour had flour mites. Still, I got away with it by pretending the teeny black bits were poppy seeds. At least, I think I got away with it. I certainly didn't overhear anyone saying: "These are not poppy seeds. These are the corpses of Acarus siro, pest of the stored grain." I'm not a great cook. I don't find turning out family meals night after night fascinating. I'm not creative. I'm lazy. I scan recipes to check out how many pots and pans are used. Four? No way! Recently, in an attempt to up my interest, I put in an order for one of those organic vegetable boxes, but the moment it was delivered I looked at it and thought: "Oh my God, what have I done? I don't know what to do with it. Take it away." It was like having a baby. I wanted to get it adopted by someone else; someone better-equipped. But having said all this, I do so love MasterChef. Who doesn't?

The show has come a long way since it used to be broadcast on Sunday afternoons, with Loyd Grossman at the helm and, if I remember rightly, contestants who were generally sensible ladies from the sensible Home Counties wearing sensible shoes and always sensibly doing something sensible with game. It was then switched to weekday evenings, with Gary Rhodes as presenter, but it didn't really take off until 2005, when the format was revamped and John and Gregg were recruited. John (Torode) is the Australian-born chef and restaurateur. Gregg (Wallace) is the fruit and veg man, who now also owns a restaurant. John is tall and rather taciturn, when not being shouty. Gregg, known as Gregg the Egg in our house, may be a bit of a one. He will keep telling jokes. "Did you hear about the Jewish kamikaze pilot," he will randomly ask, "who crashed into his brother's scrapyard?"

But there is something about this pairing that just sort of works. It may be their ability to shout mad stuff in capitals – "I WANT TO PICK THIS PLATE UP AND RUN AROUND THE ROOM WITH IT ABOVE MY HEAD SINGING SONGS ABOUT RABBIT WRAPPED IN BACON!" – or it may be their ability to ratchet up the tension where there might otherwise be none: "We know Wendi can do puddings, but can she do scallops?" Can she? Can she? Sometimes, I can only watch from behind the sofa. Whatever, the programme is now a phenomenon, attracting six million viewers and a slew of permutations: Celebrity MasterChef, Junior MasterChef, MasterChef: The Professionals, but not yet MasterChef Goes to Brent Cross and Finds It Hard to Park, Even at the Fenwick End, although it is probably only a matter of time. And for now? I'm off to MasterChef. Wish me luck! (You can do that, at least. You don't even have to get off your chair.)

The MasterChef kitchen is in Clerkenwell, at the southern end of Islington, in the basement of a University of London building. It's exciting when you tip up, because it's exactly as you see it on the telly, with that logo on the outside and everything. The logo is that "m" in a whorl that may be a "c" but, then again, may not be. I've never quite worked it out. I'm here to do the "invention test". This is when contestants must invent a dish from scratch by choosing from a selection of ingredients provided on the day. I'm led into the holding area, where the lockers are, and that grey sofa. I'm not allowed into the kitchen, where they are laying out the ingredients. They put a guard on the door. Oh heck, I think. This is starting to look serious. I start to feel nervous. I start to feel a bit sick. I ask the photographer, Dominick, to go in and spy for me. He says: "I can't do that!" I say: "Dominick, I'm not asking you to go over the top. It isn't the Somme in there. You just have to come out and whisper 'lamb' or whatever. Also, I will give you a tenner." Dominick slips in, slips back out. "Salmon," he says. There are a couple of cook books knocking about. I quickly look up salmon recipes and commit one – a baked, Asian dish – to memory. This is going to be a breeze, I tell myself. I'm going to blow Gregg and John's little socks off. Gregg is going to say: "DEEEEEE ... LISH! I JUST WANT TO TAKE A RUNNING JUMP INTO IT." John is going to say: "I'D HAPPILY PAY FOR THAT!" Thank God for Dominick, three cheers for Dominick, although, as it turns out, it isn't salmon. Can I just say – particularly if there are any Russians reading this – that Dominick Tyler is a rubbish spy, and should not be employed in any kind of spying capacity now, or at any time in the future? Ta.

I'm eventually summoned. One of the kitchen counters has been laid out with all the food while John and Gregg are standing against the wall, facing the counter. They are spotlighted. They have their hands clasped in front of them. They are serious about this. "You have to prepare one decent plate of food," says Gregg, "and it has to demonstrate your culinary ability." "You've got 50 minutes," says John. "Keep your nerve," says Gregg. "Good luck," says John. I look at the ingredients. There are noodles. There are strawberries. There are onions, tomatoes, sugar, butter, flour, capers, a big slab of fresh tuna, in the shape of South Africa, and many other things. "What do you see?" asks John. Not salmon, I want to say. (Well done, Dominick. Top espionage work!) "Um..." I say, "um ... for some reason, I thought it was going to be salmon." "We were going to give you salmon, but then we changed our minds," says John. "I think I'll do the ... tuna," I say, "with an accompaniment made from the onions, chilli, garlic, coriander..." "IT'S PARSLEY!" shouts Gregg, who can get very shouty very quickly. "And parsley," I say. "You need some wet in that," says Gregg. "And tomatoes," I say. "Do you like cooking?" asks Gregg. I bore easily, I say. Give me a recipe that calls for two onions finely chopped, and I'll chop half of one finely, roughly chop the other half, but am then too bored to bother with the second one. I'll throw it in whole, more or less. People who eat round my house probably go away thinking: "Well, that was a first. I've never had a shepherd's pie with a whole onion in it before. Good poppy-seed cake, though." Gregg says: "You're just going through the motions." I say: "Gregg, I am not talking over my motions with you. Have you never heard of personal space?"

I start chopping the onion and chilli and garlic. Badly. They hover, scaring me. John's eyes are very blue and quite cold. Gregg has run out of jokes to amuse himself with ... Ha, fat chance! "Shall I tell you what Andi Peters said to me yesterday?" he asks. Gregg, I say, do I really have a choice? "He said," says Gregg, "that if Martians landed they would think Diet Coke made humans fat, because you only see fat people drinking it." He chuckles exuberantly. John smiles one of his little tortured smiles. Gregg says he loves being on telly – "IT'S WONDERFUL!" – and also loves doing MasterChef Live at The Good Food Show. Do you get to wear one of those little headsets? I ask. "YES! I FEEL LIKE BON JOVI!"

I put the onions on to fry. John winces. John, I say, tell me what's ailing you. "Turn the heat down," he says. "Everyone thinks onions should be fried at a really high temperature, but it's a long, slow process."

I try to distract them from my own uselessness by asking about the worst MasterChef disasters. What would they be? "The worst disasters," says John, "are always about combination. Someone who decides they want to put chorizo and peach together on a puff pastry tart has gone completely nuts." "And there was the woman," says Gregg, "who had a King Edward potato and she was slicing it and putting sugar on it and I said: 'What are you doing?' She said she was making sweet potato. I thought she was pulling my leg, but she wasn't." And what's been the unlikeliest combination that's actually worked? "Partridge and pears," says John. "Who did that?" asks Gregg. "Rosie Boycott," says John. "Rosie was a great cook once you could get her to stop talking," says Gregg. A new Celebrity MasterChef begins later this month.

Meanwhile, who has been the worst celeb of all time? Lady Isabella Hervey, they say. "She probably got her butler to do her breakfast," says Gregg. "Her sausages," continues John, "were burned on the outside, raw in the middle. And when she was doing pasta with pesto sauce, she said to the guy who sets out the food: 'Where's the pesto?' He said: 'There's the basil, pine nuts, cheese...' 'No,' she said, 'I meant the jar of sauce...'" Really? Pesto doesn't give birth to itself in the jar? Seriously, who knew? "You've had 18 minutes," says Gregg.

Although the pair were teamed for TV only five years ago, their relationship goes back 20 years, when John was a chef working in London kitchens and Gregg was selling fruit and veg. Gregg was John's fruit and veg man when John was sous-chef at Quaglino's in the heady, un-credit-crunched Nineties. "It turned over 10 million a year, that place," says John. I ask if there are any foods they don't like. Gregg says he's not fond of coriander. "It always tastes to me like the smell of cat's pee." John does not like oranges. "My father had an orange-juice factory. Just the smell of oranges ... blagghhh." Gregg also says he cannot eat "ginger minge" but I think we'll skip over that, if it's all the same to you. Are we skipped? Excellent.

I go to add the parsley to the pan, which would have been a good idea, had it not made them both so cross. "Why are you doing that?" asks John. "Whoa," says Gregg. "Woody herbs like thyme and rosemary go in first. Leafy ones like parsley and basil don't go in till right at the end." I go to add lemon. "Whoa," says Gregg. "Lemon goes bitter if you cook it." "Right at the end?" I ask. "Good gal," he says. They ask if I'd thought of adding anchovies? Of course, I say. And capers? I was just about to, I say. This dish would be rubbish without capers. I put the pan on for the tuna, and make to season it. This makes them mad, too. "Oil first, or the salt will leach the moisture out," says John. (Again, who knew?)

"Were your mothers good cooks?" I ask. Gregg says his mother wasn't. "I love her dearly," he says, "but her food was not good. The difference between her chilli and her curry was a tin of kidney beans." John's stepmother doesn't sound like she was up to much, either. "She used to make curries with pineapple in them, and desiccated coconut and sultanas. It was really very nasty." Would you ever eat dog, I ask. "It would depend on the culture," says John. "If I were somewhere that ate dog, and they served it, I would give it a go." Gregg, have you ever eaten dog? "Never. Although I've been out with a few." Shall we skip again? Yes, let's.

I serve up. The tuna does look juicy, probably because John took over and cooked it. (In my time, I have served up tuna that looks and tastes like the dried-out bottom of shoe.) John lifts a forkful to his mouth. He says: "Nice salty capers, fresh herbs on top, well cooked piece of fish, probably could do with a little more seasoning, but it's very good. Very good." Gregg, who does not lift a forkful to his mouth, but just sort of puts his head in the plate, says shoutily: "THAT SAUCE IS FANTASTIC! Well-seasoned, sharp bits of caper, chilli heat at the back..." "DO YOU," I shout back, "WANT TO MARRY IT?" "I DO!" he replies. Well. Fancy.

I did OK, I think, and am quite chuffed. Will I get my cooking mojo back? Unlikely, probably, although, who knows? Next time my husband announces he's asked some people over for dinner, maybe I won't feel like stabbing him through the heart and then jumping all over his body. And today has been kind of fun although, of course, I couldn't have done it without Dominick. If you ever see a man sitting on a bench reading a newspaper with two eye-holes cut out of it ... that's him. You can be sure of it.

'Celebrity MasterChef' returns to BBC1 later this month