1. Preheat the oven to 180?C (360?F). Grease and flour a 21x11x6cm, 1.5 liter capacity loaf pan.
2. With an electric mixer beat the butter and sugar until fluffy and creamy. Add the eggs, Cointreau, orange and passion fruit juice and combine on low speed.
3. In a separate bowl, mix together flour, salt and baking powder. With the mixer on low speed, gradually add the flour mixture to the butter mixture, until well combined.
4. Pour a half of the cake butter into the prepared pan, sprinkle with mango pieces and pour the rest of the butter on top. Bake for about 45-50 minutes or until a toothpick inserted into the center comes out clean.
5. Remove from the oven and let it cool in the pan. Once the cake is cooled, remove from the pan and transfer it to a wire rack.
6. Make the icing by combining the passion fruit juice, cream and icing sugar until smooth (if necessary add more cream, until you get the right consistency). Pour over the cooled cake and if desired, decorate with candied clementine slices.

To make candied clementine slices:

1. Cut the clementines into thin slices in cross-section and discard the ends.
2. In a saucepan combine the sugar and water and bring to boil. Add the clementine slices, reduce heat to simmer. Simmer for about 30 minutes, stirring occasionally, then remove from the heat and cool to room temperature.
3. Preheat the oven to 100?C (210?F). Using a fork, transfer the slices to a baking tray lined with baking paper and bake about 20 minutes or longer if you want them chewier and more caramelized.
4. Let them cool before decorating the cake.