1. Place 2 tablespoons of the mango nectar in a small bowl. Sprinkle gelatin over top; microwave 20 seconds to dissolve gelatin, or heat over low heat, stirring to dissolve gelatin completely.
2. Beat egg substitute and sugar in small bowl until light colored and thickened, about 5 minutes. Add the remaining 1/3 cup mango nectar.
3. Add gelatin mixture; stir to combine. Fold in yogurt. Divide chiffon evenly among six 2/3-cup custard cups or molds. Freeze overnight or until set.Sauce:
4. Combine raspberries, sugar and water in saucepan. Heat over medium heat until raspberries are softened, about 5 minutes. Strain through fine-mesh sieve over bowl, forcing mixture through with back of spoon or rubber spatula; discard seeds. Taste; add more sugar to puree if too tart.
5. To serve, run bottoms of cups under warm water until chiffons slide out. Carefully unmold on plates. Spoon sauce over chiffons. Garnish with raspberries and fresh mint, if desired.