Place ham on a rack in a shallow roasting pan. Score the surface of the ham, making diamond shapes 1/2 in. deep. Cover and bake at 325° for 2 hours.
Meanwhile, in a large saucepan, combine the cider, honey, vinegar and mustard; bring to a boil. Reduce heat; simmer, uncovered, for 15 minutes, stirring frequently. Stir in the butter, chili powder and apple pie spice. Set aside 1 cup for serving.
Cook the remaining sauce until thickened; spoon over ham. Bake, uncovered, 30-35 minutes longer or until a thermometer reads 140°. Warm reserved sauce; serve with ham Yield: 10 servings (1 cup sauce).