For more than a century, the arrival of spring in Spain signals the calçotada—a festival celebrating the harvest of a scallion native to the Tarragona province. Cooks grill the calçots over a fire until the outer layer is charred, wrap them in newspaper to steam, and serve the hot onions on terra cotta tiles. Hungry festivalgoers don long bibs and dip the onions in a romesco sauce, eating as many as 20 per person. They pair them with red wine or sparkling white cava. Calçotadas take place throughout Tarragona from January until April. Spring never tasted so sweet.