Preheat the oven to 550 degrees Fahrenheit with your pizza stone inside.
Trim the roots and upper green part off the leek, and discard. Slice the leek’s stalk fairly thinly, and wash very, very well (leeks can be gritty and muddy inside, so make sure you separate the layers).
Melt 1 tablespoon of butter in a wide pan over medium heat. Add the leeks and a generous pinch of salt and cook, stirring frequently, until the leeks are soft and beginning to brown slightly, about 10 minutes.
When the leeks are done, remove them from the pan and set aside.