Pound chicken breast halves to approximately 1/4 in. (5 mm) thickness. Melt 1 tsp margarine in a small skillet over moderate heat. Add onion and cook 5 minutes until soft but not brown. Stir in sweet potato, optional wine, honey, lemon and orange peel, cinnamon, nutmeg and pepper and heat through.
Divide mixture between 4 breasts halves, roll up and secure with toothpicks. Place roll-ups seam side down in a shallow baking dish. Cover and bake at 400F (200C) for 20 minutes until chicken is tender. Meanwhile, heat the remaining 2 tsp. margarine in a small saucepan. Sprinkle the cooked roll-ups with the bread crumbs, drizzle the melted margarine over them, and brown under the broiler.