How to build a Big Mac: Can you make a fast-food feast at home?

When McDonald's executive chef demonstrated how to make the chain's most famous burger, the video went viral. Samuel Muston couldn't wait to try it out.

Last week Dan Coudreaut put on his chef's whites and took to McDonald's Canadian YouTube channel to reveal a secret. The executive chef at the golden-arch empire held up a tablet computer to the camera to show a question sent in by a viewer, a Christine H from Oshawa, Ontario. It read: "What's in the sauce that is in the Big Mac?" Quite honestly, said Coudreaut, summoning folksiness that looked like it hurt, the ingredients have been available in the restaurant or online for years. "It's not really a secret."

He then did something surprising. He showed us, over one minute 49 seconds, how to make a Big Mac at home (bit.ly/BigMacvideo). Complete with sauce. With "ingredients… that you could buy at your local grocery store". And bang – a fair few illusions were shattered and questions rose up like dandelions in June.

First, since when exactly have the ingredients of the sauce been common knowledge? Have I been napping? Who knew you could get the ingredients in shops? And will not the mighty Maccy D's edifice come tumbling if we can knock up a Big Mac at home? Oh – and why show us this at all?

Maybe the last question is the most interesting. For this video trails in the dust of an earlier "big reveal" film, one in which the company's director of marketing explains why the cheeseburger you're handed by the pimply boy in Manchester's Piccadilly Station or on Kensington High Street looks nothing like the preened version in the photographs on the wall. (Apparently, it's down to the steam in the box deflating yours and the team of stylists and snappers retouching theirs.)

What's all this about then? Seemingly McDonald's has decided that the best PR strategy is a company-wide glasnost, an opening up – giving a little more. And it seems to have worked. The video duly went viral. And I must admit, sitting at my desk, I felt a pull on a string, that unmistakeable twang of privation, a lack that wanted to be, could only be, filled by a Big Mac.

Which is odd, given that, as with lots of people, the Big Mac occupies a curious position in my moral universe, a space also home to going out late on work nights, eating a whole packet of biscuits in my pyjamas and sleeping in till mid-afternoon on a Saturday. We know they won't edify us, make us wealthy and wise – but damn me if it they don't feel and taste good.

I mean, I can see the attraction of a three-storey burger of course, oh God I can, and I understand why the UK's 1,200 McDonald's restaurants are ever-busy and why its biggest shop in the UK at the London Olympic village will doubtlessly do a roaring trade – but also the food carries what one might diplomatically call "baggage".

There was the company's use of "pink slime" (ammonium-hydroxide treatment on some meat) before 2011 and the abortive chip embargo at the London Olympics. Then there is Cordreaut's comment in June that he doesn't "see anything on the menu that's unhealthy". And yet, and yet… who hasn't dawdled outside one of the shops in a moment of weakness?

Certainly I could have dawdled last Friday. So I thought, why not make one? And set off home to do just that. But first I needed to get the ingredients, which, surprisingly, was more difficult than you'd think. Not the main ingredients, which, as the famous jingle said, consists of "two all-beef patties, special sauce, lettuce, cheese, pickles, onions – all on a sesame-seed bun".

The difficulty came with the sauce. I had the paprika in, the mayonnaise was on its shelf with hotdog mustard in the fridge, and the white wine vinegar and powdered onion and garlic were where I left them at the back of the cupboard. But the sweet pickle relish, the thing that gives the sauce the uplifting sweetness – nowhere to be found.

"We have sweetcorn relish and we have pickle relish that is like Branston," said the not altogether helpful lady in the supermarket near me. And it was the same story in the other two supermarket chains I visited. Eventually after much Googling, a lonely jar of all-American relish was located at Partridges in Chelsea, which may go to show why that shop has a Royal Warrant and my local supermarkets do not.

So, anyway, with the ingredients arrayed around me and the knives, whisks and what-not out and ready, I switched on Coudreaut and following his lead, made the sauce first. But, oh, wait a second. Although he tells us what's in the sauce, he doesn't give quantities. Not very Delia, that.

No matter, though. After some trial and lots of error, I have a sauce. And you know it tastes pretty good. In fact, my housemate, a fast-food gourmand, declares it a resounding success: "Tastes exactly like the sauce in the one at Liverpool Street."

Now it's time for the rest of what Coudreaut calls "the Big Mac experience". The chopping of the onions into peculiarly small cubes, the slivers of lettuce, which he explains are there for "moisture and crunch". The forming of the beef mince into thin patties, which is accompanied by a PR-ish reminder (one of many) that the meat should be 100 per cent cow, "just like in the restaurants". The toasting of the buns in a dry pan comes next, which, again, following Coudreaut on screen, I accompany with a jaunty whistle.

It is at this point, the patties cooking away in the pan, that I learn something that I never before knew. As he prepares the three decks for their meaty cargo, he explains that the base is apparently called a heel, the middle a club and the top most bit of bread a crown. I know not why, but this information pleases me.

So meat cooked, gaggle of housemates hovering, it is time for the spreading of the sauce – and the assembling. And there it is: tall, proud and perfectly poised, I have myself a Big Mac, which incidentally looks much better than the one on screen and, indeed, the one I picked up from the restaurant. But then again it takes 1.5 minutes to make a Big Mac in a busy McCafé and I've taken probably 10 times longer.

Question is, what does it taste like? Fabulous, is the answer. The pillowy buns, with their characteristic McDonald's pan-toasting, give way to the meat patties, with their light browning and melting slice of cheese that may surpasseth all understanding but somehow works. And combined with that sauce, with its slight sweetness and profound gooeyness, the very thing that I now recognise makes a McDonald's burger, it is a triumph. A filled housemate declared it "a technicolour version of the mono thing you get for £2.29 down the road". High praise.

So will I now be forever in the kitchen whipping up McDonald's-style burgers? Probably not. But if the weather permits me an invitation to a barbecue this year, I'll make it my business to have the sweet pickle ready and plenty of mayonnaise, mustard and seasoning at the ready, because if there is one thing every charred burger can benefit from it is that lovely, not-so-secret sauce.

The Big Mac – "Sam Style"

For the sauce:

2 tablespoons mayonnaise
1 - 1.5 tablespoons sweet pickle relish
1 - 1.5 tablespoons hotdog mustard
White wine vinegar to taste
1.5 teaspoons garlic powder
1.5 teaspoons onion powder
1 teaspoon paprika

The rest:

2 sesame seed buns
Half an onion, finely diced
Handful of lettuce, finely chopped
2 slices of gherkin
Minced beef
Slice of cheese

Whisk sauce ingredients in a bowl – taste and be ready to make adjustments. Now set aside. Discard crown of second bun, keep the base. Form beef into 2 thin patties.

Toast the first bun and second base in a dry pan. Smear bottom two sections with sauce.

Add patties to lightly oiled pan, fry until both sides are browned. Season lightly with salt and pepper.

Add onion and lettuce to bottom two layers of the bun. Then add cheese slice to bottom and gherkin to middle.

Place beef patties on bottom layers. Assemble your tower of beef – and scoff.