Chocolate-Hazelnut Mousse with Marinated Mango

Soak the gelatin in cold water. Melt the chocolate-hazelnut spread in a small saucepan or in the microwave. Separate the eggs and beat the egg yolks, with the bourbon-vanilla sugar, orange zest and Cointreau in a double boiler or heatproof bowl over a saucepan of simmering water until light and frothy. Squeeze the excess water from the gelatin and stir into the egg yolk mixture until dissolved. Stir in the melted chocolate-hazelnut spread. 

Beat the egg whites until stiff. Beat the whipping cream until stiff. Fold the egg whites and whipped cream into the egg yolk mixture, divide between 4 dessert glasses and refrigerate for 1 hour. 

Peel the mango, cut the flesh from the pit and slice very thinly. Zest and juice the limes. Whisk the lime juice, lime zest, brown sugar and Cointreau together until smooth. Place the mango slices in a shallow dish and pour the lime juice mixture on top. Marinate in the refrigerator for 30 minutes.