The sweet onion or "calçot" is a tender, white, sweet spring onion which, flame grilled, is the basis for a "calçotada". It is a delight to taste, capable of satisfying the most demanding palates.

Each of the shoots from a fully-developed white onion that has been replanted in the earth is called a calçot. When the onion has germinated and grown, it is pulled up and, after being kept for a season, it is planted again in such a way that it is onion half buried. As the plant grows, it is necessary to surround it with earth or "put its boots on" (in Catalan, "calçar", giving it its name). The stems must be between 15 and 25cm high of 'white leg'. These sweet onions, flame grilled, are the main part of the "calçotada", a typical, traditional culinary feast in Catalonia. The most famous is held in Valls on the last Sunday in January.