Rinse duck under cold running water; pat dry. Prick skin all over. Combine remaining ingredients in non aluminum saucepan, stirring until smooth. Cook until thickened & sauce comes to boil. Place each breast in center of heavy duty foil. Pour 1/4 sauce over each. Seal tightly around duck. Grill over med heat 1 hour or until tender. Remove duck from packet, reserving liquid. Cook skin side down on grill until browned. Slice thinly. Use leftovers within 1-2 days.
Servings: 4