Add the mushrooms to the fat left in the pan. Season with the thyme and 1 teaspoon of the salt. Cover and cook, letting the mushrooms release their juices, about 3 minutes. Uncover, increase the heat to high and cook until the liquid in the pan is gone and the mushrooms are browned all over, about 6 minutes. Add the scallions, and cook until wilted, about 3 minutes. Scrape the contents of the pan into a large serving bowl, and let cool 5 minutes.