In 1898, a farmer called Xat de Benaiges, in Valls, Catalonia, dug up his white onions five months after they had been sown and replanted them. His experiment gave birth to the calçot - a vegetable that is registered with the European Union's Protected Geographical Indication scheme and can only be produced in four Catalan counties. It's the champagne of onions. To try this sweet-tasting delicacy no longer must you travel all the way to the northeast of Spain, where 31 million calçots are churned out each year between November and March, and the annual Gran Fiesta de la Calçotada, in Valls, attracts 30,000 visitors. Rustico restaurant, in Lai Chi Kok, is, for a limited time, flying the vegetable to Hong Kong, and its Catalan chef will be serving it in traditional styles. Purists will be able to order calçots served on hot terracotta roof tiles (they keep the vegetable warm) - in Catalonia, they'd have been grilled on a high fire and wrapped in newspaper, to be eaten with bare hands. Other dishes include calçots cooked in confit and stir-fried, and a tempura variation. According to chef Juanjo Carrillo, the most customary way to enjoy them is grilled with salvitxada sauce - similar to romesco but thickened with toast rubbed with garlic. He also serves his calçots with anchovies and mint, for a stronger, fuller flavour. Want to eat calçots the true Catalan way? Put down the cutlery and, using your hands, pick up a grilled calçot by its green leaves, dip it into the salvitxada and raise it high above your head. Lean back, lower the whole thing into your mouth and bite off the top of the white, juicy root. Don't worry, there are videos on YouTube to study before you take the plunge. Rustico's Catalan calçot menu is available from noon till late until February 11. Rustico is in D2 Place, 9 Cheung Yee Street, Lai Chi Kok, tel: 2743 4511.