To serve, in small bowl, mash remaining 1/2 cup raspberries with fork. Spread raspberries over frosting mixture. In small resealable freezer plastic bag, place remaining 1 cup baking chips and the oil; seal bag. Microwave on High 1 minute. Squeeze bag to mix; microwave in 10-second increments, squeezing after each, until chips are melted and smooth. Cut small hole in one bottom corner of bag; squeeze bag to drizzle mixture over top of dessert. Cut into squares. Store in refrigerator.