The Inside Story Behind London's Cube-Shaped Croissant That Went Viral - Exclusive

In September 2022, head baker Mustapha Ait Elamouam wanted to offer customers at Le Deli Robuchon, owned by the world-renowned French chef Joël Robuchon, something new. He was inspired by the cube-shaped croissant he was beginning to see within the pastry world (like the ones from Karma Bread Bakery in North London). Ait Elamouam set himself the task of putting his own signature on a version to be baked and sold in Le Deli Robuchon in London.

Le Deli Rubochon opened in 2019 and sits on the busy Piccadilly Road in central London, just steps away from Green Park, one of the city's Royal Parks. The area is known for its foot traffic. It is home to several tourist destinations, including The Ritz and Picadilly Circus, and it is within walking distance from a plethora of historic buildings and institutions like the famous Royal Academy of Art and, of course, Buckingham Palace. Le Deli Robuchon benefits from this location and the high standard of its Michelin-starred namesake Joël Robuchon, drawing in visitors from near and far into its boulangerie, sampling viennoiserie, patisserie, as well as its savory quiches, salads, and sandwiches.

In January 2023, Le Deli's new Le Cube Robuchon had its first viral moment on social media, with an increasing number of sales, queues, and customers eager to get their hands on the geometric-filled pastry. The demand for Le Cube continues to rise by the day. Here's how it all happened.

When it comes to French patisserie, precision, technique, consistency, and quality are critical factors in any creation, especially ones with the prestigious Joël Robuchon name attached to them. However, tradition should not get in the way of innovation, and Ait Elamouam wanted to push for something new. "Why should we need to keep [a] croissant in its traditional shape? We need to do something different," he told us.

In September 2022, having seen the cube-shaped croissant around, Ait Elamouam began playing a game of Goldilocks, testing different-sized cubes that were either too big or too small before settling on the perfect size. Ait Elamouam tested and retested 10 times. When the pastry was too large or without filling, it became dry. When it was too small, the flaky croissant characteristic got lost. If the outside was too sweet, the palate became coated, and customers would be unable to taste the nuance of any flavors inside. Then, of course, there was creating the perfect thickness of the cream fillings. "I know the English people, they like it when there is a garnish. I wanted to make a cube that was garnished with cream, but kept the crispness of a croissant," he commented.

Achieving the ideal size, shape, and consistency in just a few short months was an impressive feat. In November 2022, Le Deli displayed its first dozen Le Cube Rubochon in three flavors (more on that later).

The start of Le Cube's popularity is all thanks to an influencer, according to Giovanna, one of the shop's managers. In January, Le Deli Rubochon invited an influencer from TikTok to sample a different pastry. His curiosity peaked by just seeing Le Cube (who wouldn't really, they're stunning), so he included one of the pastries in his social media posts. "We invited an influencer from TikTok to come and try one of our king cakes, and he saw [Le Cube] when he came to collect it, and there we have it," she says. The pastry took off, accumulating more and more customers purposefully coming in just to try the perfectly right-angled pastry.

The trend feels reminiscent of the cronut era of roughly 10 years prior. The cronut became a global food trend that always seemed to have more demand than product (as is the ratio of all good trends). It originated from the mind and hands of Dominique Ansel in an upscale pastry shop in New York City. However, you can still find references to it today in various locations.

After chef Ait Elamouam had finally perfected his version of Le Cube, Le Deli Robuchon premiered just 12 Le Cube Robuchon in November 2022. The shop's manager Giavanna says it took a little while for the pastry to become popular, with the team slowly ramping up the production as they went to ensure quality. "We can sell 200 in just one hour! We didn't expect that but it's good," says Ait Elamouam. "It's hard to keep the quality when we have [to] sell 700, but we have to so that people come back. If we sell something that wasn't good, no one would come back."

Today, the establishment sells nearly 350 on an average weekday, with several peak times, typically once in the morning and once in the afternoon, when the product comes out fresh and ready to fly off the bakery shelves. The lines at the weekend are even more significant than during the weekday— sales consistently now hover at the 700 mark, which translates into endless queues out of the shop from opening until closing. Shop manager Giovanna, who has been at Le Deli since its start in 2019, says she's never seen anything quite like it.

There are three signature flavors: vanilla, chocolate, and matcha with raspberry. Ait Elamouam wanted to make sure two standard crowd-pleasers, chocolate and vanilla, were on offer. The wild card flavor was matcha. The vanilla comes with just a dusting of powdered sugar on top. It is filled with subtly sweet vanilla bean-flecked cream or vanilla cremeux. The chocolate has a glistening layer of ganache and a sprinkling of crunchy, pea-sized chocolates, and a lighter mousse-like filling inside. The matcha and raspberry cube (which, after trying them all, happens to be our favorite) is topped with a coating of light matcha-infused glaze and raspberry with smooth matcha cream darted with tart raspberries inside.

While there is a strong divide amongst staff as to which flavor is the favorite, all three flavors fly out the door just as quickly as they are laid down in the case. One of the most common errors, cautions the manager, Giovanna, is when customers mistake the matcha flavor for pistachio.

Giovanna also suggests coming with an open mind about matcha, noting that some of the customers who come with pre-conceptions about their feelings towards the tea are missing out on trying something delicious. The combination of gently sweetened cream, slightly bitter matcha, and acidity from the raspberry is not to be missed (unless, of course, you're allergic. In which case, carry on).

Want to create a fever pitch for an already in-demand product? Drop a few limited editions into the mix. That's just what Le Deli Robuchon did, first for National Croissant Day in January and then again on Valentine's Day, with the launch of the rose and raspberry Le Cube Robuchon, available only on the day.

Usually only available in person without any option to pre-order, Le Deli also waved the rules on the Le Cube Vanilla for a mere 24 hours, making it available to order for delivery through Deliveroo only. We can only imagine how quickly they sold out.

And, for a special upcoming event, London-based fans of Le Cube, you'll want to keep your eyes peeled. Chef Ait Elamouam reveals there will be a new, limited edition flavor, a regal red velvet Le Cube with mascarpone and vanilla, exclusively available in honor of the King's coronation taking place in May. Better keep your phones open to the Instagram account for a sniff of its first drop, and get ready to queue.

With technical skills and consistency standards so high, these are not easy pastries to whip up at high speed or volume. Ait Elamouam, who is based in Marrakech, makes frequent trips to London to examine the quality and ensure all involved are expertly trained.

"There is also a knack for getting the fat content right," says Ait Elamouam, "so that the pastry is still light like a croissant rather than feeling too heavy." He explains this is down to the ratio of butter used in the dough. It becomes more technical than the croissant when it comes to molding and baking to perfection, not to mention the right thickness and texture of the cream inside (not too hard, not too thin) or the topping which, if it has too much sugar, will coat the tongue, taking away the nuance from the other flavors inside. "When you eat sugar, you can't feel any flavor, so we have to keep it with the right amount of sugar and the right ingredients," says Ait Elamouam.

It is also down to the quality of ingredients, as Ait Elamouam emphasizes, "If you have good ingredients, you will have a good flavor." All of these factors help to explain Le Cube's retail price of £6.95 or about $8.65.

Though already in existence prior to its newfound viral status, Le Cube Robuchon has gained fans across a broad spectrum of people, from locals stopping in for a coffee and to see what the hype is about, to tourists who visit the bakery and shop solely for Le Cube, to celebrity sitings. For a sample selection of customers, just look up the #lecube and #lecuberobuchon hashtags to see the wide variety of folks who've sunk their teeth into the cream-filled pastry, from digital creators and influencers to everyday pastry-loving-people, including many dedicated souls who have had to try several times before securing the viral pastry.

Its popularity has also sparked inspiration (or perhaps just heightened awareness that the pastry had been on offer all along) with cube-shaped cuties cropping up in other areas of the world, like at Julien Boulangerie on the Upper East Side of New York City, and Andersen & Maillard in Copenhagen. And to think, its popularity at Le Deli Robuchon was purely accidental.

There are new flavors in the works for the regular menu in London, but lips are sealed on the exact details or when it might be coming out. Staff from the front of the house like Giovanna, to the back of the house like Ait Elamouam, are now anticipating these changes and the likelihood of further increased popularity alongside them. Both people discussed how they will work to maintain the excellent quality associated with their name and products. "Whatever we do, we want to make the people happy and keep the quality high," says Giovanna.

Meanwhile, head baker Ait Elamouam is also being kept exceptionally busy, with a recent opening of Le Deli Robuchon in Tel Aviv and Madrid. There is also a slew of new openings for Robuchon on the horizon, including in Morocco and in Qatar, both of which will carry Le Cube according to Ait Elamouam. Madrid, he says, is currently being pegged as the next possible Le Cube destination after that. Sadly, the U.S. is not currently on the radar, but all the more reason to travel, we say. "I thought it would be good," says Ait Elamouam, "but not like that! I'm so happy people like it."