It sounds like a kind of cruel joke. Taking the world's best pastry chef, who usually cooks for the creme de la creme at the Ritz in Paris, and seeing if could satisfy the sweet tooth of hardscrabble Americans who eat from fast food trucks.

But despite his almost non-existent English, and his equally rudimentary understanding of the down home American palate, Francois Perret was game for the experiment, which was shot for the new Netflix series, "Chef in a Truck".

So much so, that the man who was pronounced the best restaurant pastry chef on the planet last year by the august World's Great Tables even created two US-inspired desserts for the Ritz. For two weeks, Perret travelled around California trying out local treats and traybakes and then tried to come up with ways to refine them and still please the average American.

The 39-year-old Frenchman told AFP that he loves watching people eat his creations because their expressions "do not lie" -- a chance he rarely gets at the Ritz. "It was great to take part in an adventure like this, to be in direct contact with the people who are eating your food," he said.

Culture shock

Even so, the culture shock between the sophisticated palates of the jetset, the pressed linen tableclothes and scurrying waiters of the Ritz and the lunchtime truck stops of workaday Los Angeles could not be more stark.

Technically too it was also a challenge for a chef used to the best equipped kitchens in the world, with his brigade of 30 highly-trained cooks, to be reduced to cooking in a truck with only two helpers.

But the pay-off for being forced out of his "comfort zone" was worth it for Perret, whose new creations normally have to be tasted and signed off by the Ritz's strict kitchen hierarchy.

"There was no service, you had to do everything yourself," he said. "You are there in front of your customers and you see their reactions. When someone eats (in front of you), they cannot lie. You see straight away from their face whether it works and they like it or not," he said.

While Perret occasionally goes out into the dining room to present his desserts at the Ritz, usually he has to peep out through the kitchen door or ask waiters for feedback. However, his big challenge in the land of sugar and syrup-drenched cookies and cakes was to make goodies that were nowhere near as sweet but just as moreish.

To do that, Perret latched onto the American habit of eating savoury dishes with sweet ketchups and sauces, coming up with pear and honey tacos.

'Sugar unites'

Perret also took that American picnic and camping institution, the s'more -- fire-roasted marshmallows sandwiched between biscuits with chocolate -- and gave them a haute cuisine twist. "The base of my s'mores is puff pastry, and there is nothing more French than that. Stuffed with chocolate ice cream, we then dipped them in molten marshmallow. "It is a pastry which looks very American but the conception is very French," he added.

Perret scorched every one with a blowtorch as a little nod to the camp fire and the treat's scouting heritage. A version of the s'mores he created, as well as the tacos -- this time made with apricots, which are now in season in France -- are on sale in the Ritz's very own patisserie. Despite the gulf in gastronomic cultures between France and the US, "we are not all that different from each other," Perret insisted.

Sugar "unites people", he said, "no matter how it is used. It has more power of seduction" than any other ingredient in the gastronomic arsenal. Almost from the moment that we start to eat solids as very young children, "we start mythologising patisserie", Perret argued. "We punish kids by threatening to take away their dessert, not their meatloaf," he added, with a wink to another very American dish which is actually based on a French classic.