1. Place each peach half in 6-ounce custard cup or small bowl. Mix remaining ingredients except margarine until well blended. Fill each peach half with about 1 tablespoon macaroon mixture. Top each with 1 teaspoon margarine. Arrange custard cups on 10-inch plate.
2. Cover with waxed paper and microwave on medium (50%) 4 to 6 minutes, rotating plate 1/2 turn after 3 minutes, until peaches are tender when pierced with fork. Let stand uncovered 10 minutes. Serve warm or cold and with ice cream if desired.