Place the carrots in a large skillet. Dot with the butter and sprinkle with the sugar and 1/4 teaspoon salt.
Add enough cold water to come halfway up the sides of the carrots. Simmer, partially covered, until the carrots are tender and the liquid has reduced to a glaze, about 20 minutes. (If the carrots are done before this point, transfer them to a bowl, increase heat to high, and cook the liquid, uncovered, until reduced. Return the carrots to the pan and toss.)