A masterclass from René Redzepi is less a cooking lesson than an initiation into a new religion. Sure, there are ingredients with which to become acquainted, flavour combinations to think about, techniques to master. But there's other stuff to understand as well: a way of thinking about food, a way of being. "People need to realise that food is too cheap," Redzepi says at one point, as he roars about the kitchen of his airy Copenhagen apartment, arranging platters of greens and ceramic bowls of soft fruit. "The faster you want to be at cooking the more you're going to have to learn to cook," he says, or "Everything is good with butter. If an ingredient is not good with butter it is not a good ingredient." Solemnly I note down his thoughts as if they are the new catechism. Perhaps they are.

In the seven years since Redzepi opened his restaurant Noma on a canal front in the heart of the Danish capital, it has come to be regarded as not simply an interesting luxury restaurant but as a key voice in the conversation about how we feed ourselves in the 21st century. Redzepi's steely-eyed commitment to a Nordic agenda, in which nothing will appear on his menu unless it is from the region in which he is located, has made words like "local" and "seasonal" sound like mere platitudes. He really bloody means it.

Last year when Noma knocked El Bulli off the top spot in the annual list of the world's 50 best restaurants – an accolade it retained this year – a torch had been passed. The modernism of Ferran Adrià felt old hat; now it was all about the best ingredients, treated as sympathetically as possible. If an ingredient-led approach really is a new religion then the half-Danish half-Macedonian Muslim Redzepi must be its high priest.

And now here I am, in church, preparing to worship. It's a laidback place. Piano jazz plays on the sound system. Redzepi's second child, Genta, was born three months ago and she's here too, for a while lodged on the hip of his wife Nadine; at one point passed into my care while mum makes coffee. Redzepi's number two chef, a quiet, big-browed Yorkshireman called Sam Miller, is also here. "I have five Brits in my kitchen," Redzepi says. "I like the way they think and work."

In just a few days, Redzepi will host some of the biggest figures in the culinary firmament at the MAD FoodCamp, two days of gastro-seminars in a circus tent pitched in a central Copenhagen park. (The name is a tautology; mad is the Danish for food). Redzepi, who came up with the idea, has been working on it for two years. "I saw it as a responsibility to do this," he says. "We have a chance to educate, and for chefs to realise that the choices they make really can benefit people." And yet for all these mission statements, there is something relaxed about the man, almost impish, as if cookery is for him an adventure.

That's how it feels as we confront the central station in his kitchen, loaded with ingredients. Today he will teach me to make three dishes. All of them use foods freely available in Britain. "In terms of plant life Britain and Denmark are pretty much the same," Sam Miller tells me, as he arranges ingredients. None of what we're doing today, Redzepi says, is designed for the menu at Noma. "These dishes are not refined enough. This is home cooking, but it is home cooking in the style of Noma."

And so we get to work with a fistful of daffodil-yellow unsalted butter, churned from the milk of cows fed on biodynamic pastures. Redzepi loves the biodynamic movement, the way crops are grown on the lunar cycle. He loves it almost as much as he loves the butter. I melt a dollop of it in the bottom of a cast iron pan and then add a whole cauliflower from which I have sliced off the bottom. "Boiled cauliflower is terrible. But this pot roast cauliflower is something special." Branches of pine, spruce and juniper are then placed around it for aromatics. We put the lid on. And now? "Now," he says, quoting an American chef friend, "it's 35 minutes of don't fucking worry about it."

While the cauliflower is cooking, we start the second dish, by laying skin-on baby beets on a piece of foil which will form a pouch. "I love the earthiness of beets, the sweetness, the lightness. And this is so simple anybody could do it." I am instructed to layer the beets with sprigs of fresh herbs, plucked from planted pots arrayed before me: various thymes and sage, rosemary, "whatever the hell you like". Redzepi the chef may be doctrinaire but Redzepi the teacher is very laidback.

Next he gets me to taste a little apple vinegar. It is light and fresh and not at all the bash of teeth-baring acidity I'm used to from vinegars at home. Redzepi is serious about his vinegars. He often uses them instead of salt as a seasoning. "At the restaurant we have perhaps 25 vinegars. At home, though, I have just four which is all you need in your kitchen." A glug of the apple vinegar is added to the beets along with a knob or two of butter, and the foil is sealed up into its closed pouch which goes into a moderate oven.

By now the kitchen has a rich, earthy smell from the cauliflower. We take a peek, lifting it gently from the pan. It is a rich bronzed colour, from the caramelisation, and the rest of the vegetable has gently steamed. We take it out and leave it to cool caramelised-side up, while we make what Redzepi calls a vinaigrette using the buttery cooking juices and lightly warmed yoghurt whey. A glug of the apple vinegar and we have a powerful broth to accompany the cauliflower. He finishes the dish off with a dollop of cream, which has been infused with fresh grated horseradish overnight, before being strained and whipped. "Horseradish gives it a lovely acidity," he says. The lightest sprinkle of salt on the cauliflower and the dish is finished. "I just serve the whole thing in the middle of the table and people help themselves." It has been very simple to do, but the effect is remarkable. There are big umami flavours, but also a lightness. That's one for the next dinner party.

We check the beets. Horror! I didn't seal the foil properly. The crimson juices have leaked out and singed on the bottom of the pan. The hole has also slowed down the cooking process. I feel like I've failed my teacher. "No worries," he says, soothingly. "It happens." We tighten the foil. To make up for it I show off my knife skills by finely chopping half a shallot to go into a mortar along with big fat blackberries, leaves of lovage and fresh angelica seeds. He reassures me that coriander seeds and leaves work just as well. I am instructed to bash the fruit and aromatics into a sludge, which will then be passed through a sieve to make a sauce. "It's an abstract gazpacho," he barks at me. "It's a Scandinavian pesto, it's a Danish molé." I taste the sauce. It is certainly very special: fruity, but savoury too and aromatic.

He asks me if it needs something to soften its acidic edges, and gives the impression that he genuinely cares about my opinion. It's empowering. I agree it does. He gets a jar of honey. "Never use sugar. Sugar is the enemy." We let the beets cool, then peel their skins and slice them in half. I add a few sprigs of fresh herbs, and spoon the sauce in between the beets. Finally, Redzepi takes a bottle of olive oil from beside his home stove. I look at this Nordic food warrior, aghast: he's using the über Mediterranean ingredient. It's like watching the chief rabbi making a bacon sandwich. "This is just home cooking," he says. "A little of this won't hurt." The end result is beautiful to look at, and thrilling to eat, a combination of sweet and sour, of earthy and vegetal.

The final dish is the quickest to knock up but requires the most technical skill. First we make an emulsion using melted butter – what else? – and black tea. "All Brits drink tea," Redzepi says. "So I thought it would be a good ingredient." I beat the liquids furiously until the fat and water bind. I am instructed to very gently warm a little of this in a pan. I throw in torn leaves of thick-stemmed chard, turning them so they are coated in the emulsion. Next come frilly celery tops and leaves of ground elder. When the chard has just started to wilt I add the meat and liquor from three oysters, which I had shucked just minutes before. It all goes on to a plate and we finish the dish with a glug of apple vinegar and some split cobnuts. It is, in essence, a warm salad; one full of the freshness of land and sea. Eating it makes you feel you are being good to yourself.

Redzepi is eager to know what I think. I tell him that all of a sudden I think I'm a genius. Look what I did! He laughs. "Recipes are only guidelines," he says. "You have to use your natural-born skills as a human being to taste a dish. It is the cook who makes the difference." Today, he says, I have been the cook. We both know this isn't true; that I have been merely his student. And yet to say the morning has merely been instructive would be a gross understatement. As a cook I tend to rely on lumps of animal and the application of a lot of fire. Today Redzepi has shown me what you can do with things that never had a pulse, has inculcated me in the way of the vegetable. I have been to church. I have listened to the lessons. I have come away a disciple.

Now try the recipes for yourself