Glaze: Whisk the mustard with the apple cider, honey, thyme and garlic; set aside.
Roast: Preheat the oven to 425° Toss the potatoes with the carrots, onions, oil, thyme and half the salt and pepper. Arrange in an even layer in a large roasting pan. Roast for 30 minutes or until lightly browned. Meanwhile, pat the pork dry with paper towel. Season all over with remaining salt and pepper. Place over the vegetables. Pour the broth and wine into the roasting pan. Reduce the temperature to 325°. Roast, basting every 30 minutes with the glaze, for 2 to 2 1/2 hours or until an instant read thermometer registers 145°F when inserted into the center of the pork. Transfer the pork to a platter or carving board; tent with foil. Using a slotted spoon, transfer the vegetables to a serving bowl; tent with foil. Transfer the cooking liquid to a small saucepan; bring to a simmer. Whisk the flour with the apple cider until smooth. While whisking constantly, slowly pour the apple mixture into the saucepan. Cook, stirring, for 5 minutes or until thickened. Season with salt and pepper to taste.
Use 1 tsp dried thyme leaves in place of the fresh thyme. Replace the wine with the same amount of chicken broth.