Planted in trenches, like an onion, as a single bulb, and successively increasing the depth of the soil around the stems throughout autumn and winter (see earthing up), they sprout into 4–10 shoots, roughly the shape of small leeks or scallions.

In these events, they are grilled over a hot fire, wrapped up in newspaper, served on terra cotta tiles and eaten, after peeling with bare hands, by dipping them one by one in special sauce (made with almonds).

[2] The word "calçar" itself literally means "to shoe",[3] and ultimately derives from the Latin calceus, a type of footwear that covered the ankle and lower shin - hence its use by analogy in this context.

The origin of the variety is disputed, but one of the most commonly accepted versions [unsubstantiated] of its history is that they were developed by Xat de Benaiges, a peasant farmer from Valls around the turn of the 20th century.

He is said to have been the first to have planted the sprouts of garden onions, covering them with earth so a longer portion of the stems remained white and edible.