Calçotada is the name of a spring festival in Spain that celebrates an oniony-type vegetable known as the calçot. Great quantities of calçots are grilled and then served with romesco, a sweet and savory pepper sauce. In my part of the world, there's an oniony-type vegetable that closely resembles the calçot. It's called a leek, and it's also widely available in the spring and fall. This recipe uses leeks, but it's inspired by the Calçotada's marriage of caramelized, roasted onions with yummy pepper sauce.