Melt 3 tablespoons unsalted butter in a large 12-inch skillet over medium heat. Add 2 pounds peeled and sliced carrots, 2 tablespoons gochujang, and 1 teaspoon kosher salt. Cover and cook, stirring occasionally until the carrots start to soften, 4 to 5 minutes.
Stir in ½ cup water and ¼ cup honey. Increase the heat to medium-high and cook uncovered, stirring occasionally, until the liquid is mostly reduced to a thick glaze that coats the carrots well, and the carrots are just tender, 8 to 10 minutes. Garnish with 1 thinly sliced medium scallion and toasted white sesame seeds if desired.
