Leeks, like so many fall vegetables, require both heat and time to transform them from raw and tough to tender and delicious. Of course, I'm partial to grilling, but roasting them on the grill from start to finish can take upwards of 30 minutes or more, which seems like an awful lot of charcoal for just one vegetable.
One method of shortening the grilling time of vegetables is to par-boil them. I'd tried it before with sweet potatoes and butternut squash, but found that the method deteriorated flavor and texture a little too much for my liking. I decided to try it again here, and it turns out to be a great method for leeks. Here's how I did it.
After trimming off the dark green tops, splitting, and then thoroughly washing the leeks, I placed them in boiling salted water and cooked them until they just started to soften—about 5 minutes—then plunged them in an ice bath to stop their cooking and preserve the color.
With partially cooked leeks, I was able to forgo slow-roasting over indirect heat on the grill and skip straight to direct grilling, letting them cook over the coals until charred on both sides. This took under ten minutes, and during this time, they completely softened throughout.
The blistered black outer layers of the leeks had a nice crispness that held the distinct flavor of the grill. The tender insides were mildly sweet and oniony, which was a flavor and texture that paired very well with a rich and creamy Spanish Romesco sauce made from roasted tomatoes and red peppers.