Place the mangoes and powdered sugar in a food processor and puree.
In a large bowl, place the gelatin with the cold and hot water, lemon juice, nutmeg and cinnamon. Stir and then let sit for 5 minutes.
Add the mango puree to the gelatin mixture. Let sit for 20 minutes.
Beat one cup of the whipping cream to soft peaks and gently fold into the mangoes.
As this point you can either spoon the mousse into individual dishes or place the entire amount into a spring-form pan for slicing later.
Let the mousse chill in the refrigerator at least 4 hours. Top with fresh whipped cream.
Or serve with blackberry coulis
*You can omit the gelatin and water, producing a softer consistency-more like a pudding.