In a large skillet over medium heat, arrange the mushrooms in a single layer. Cook, undisturbed, until beginning to brown, about 4 minutes. Sprinkle the mushrooms all over with the salt. Cook, stirring, until the mushrooms begin to release liquid, about 4-5 minutes. Continue to cook, stirring occasionally until the mushrooms are tender and all of the liquid in the skillet has burned off, about 2 more minutes.
Add the butter to the skillet and cook, stirring until the butter melts and the mushrooms have turned a golden brown, about 5 minutes.