Preheat the oven to 400 degrees F.
Cut off and discard the ends of each butternut squash. Peel the squash, cut them in half lengthwise, and remove the seeds. Cut the squash into 1 1/4 to 1 1/2-inch cubes and place them on a baking sheet. Add the melted butter, brown sugar, salt, and pepper. With clean hands, toss all the ingredients together and spread in a single layer on the baking sheet. Roast for 45 to 55 minutes, until the squash is tender and the glaze begins to caramelize. While roasting, turn the squash a few times with a spatula, to be sure it browns evenly. Taste for seasonings and serve hot.