Cook carrots in a large pot of boiling water until tender, about 8 to 10 minutes.
Strain carrots, leaving just enough of the cooking water to cover the bottom of the pan; set carrots aside.
Stir in brown sugar and butter; simmer and stir until butter melts.
Return carrots to the pot and toss to coat. Cover and let sit for a few minutes to allow flavors to mingle.