In a blender jar, add mango pieces and sugar. Puree until smooth.
Meanwhile, melt the cooking chocolate with 1 tablespoon of cream in a double boiler. Set it aside until it is just warm.
In a large mixing bowl, add whipping cream, vanilla essence and icing sugar. Whip on high speed until the cream is doubled up in volume. It should fall in soft peaks, stop whipping at this point.
Add the prepared mango puree to the whipped cream. Gently fold it in until both the cream and mango puree are well mixed.
Now prepare the serving glasses by pouring 1-2 teaspoon of chocolate ganache all around it.
Fill in the glass with prepared mousse. Top off with cut mango pieces.
Keep it in the fridge for 2-4 hours before serving.