Preheat oven to 400°F. Prick sweet potatoes all over using a fork. Arrange on a baking sheet; roast until just softened, 35 to 45 minutes. Let potatoes cool slightly until easy to handle, about 10 minutes. Halve potatoes lengthwise; place cut side up in a baking dish greased with coconut oil.
Meanwhile, bring brown sugar, maple syrup, coconut oil, ginger, vanilla, orange zest and juice, star anise, cloves, and cinnamon to a simmer in a small saucepan over medium. Simmer, stirring often, until thickened to a honeylike consistency, 22 to 25 minutes.
Spoon syrup evenly over sweet potatoes. Bake at 400°F until syrup has thickened and sweet potatoes are glazed and just beginning to brown around the edges, 25 to 30 minutes. Remove from oven, and sprinkle evenly with flaky sea salt. Serve hot.
