Preheat the oven to 450 degrees F and adjust the rack to the middle position.
Place the sweet potatoes in a large mixing bowl. Pour the melted ghee, 1 teaspoon sea salt and pepper over the potatoes and toss until coated.
Arrange the potatoes in a single layer on a baking sheet lined with parchment paper. Roast in the oven until the bottoms are lightly browned and tender when pierced with a paring knife, about 30 minutes.
While the potatoes are roasting, whisk the broth, honey, arrowroot and 1/2 teaspoon sea salt in a small bowl.
Remove the pan from the oven and scatter the smashed garlic in-between the potatoes on the pan. Pour the broth mixture around the potatoes, avoiding the tops of the potatoes. Continue to roast until the liquid has slightly reduced, about 15 minutes. Transfer the potatoes and garlic to a serving platter and pour the sauce in the pan overtop. Sprinkle with thyme and serve.
Adapted from America’s Test Kitchen