To make the gingerbread, combine flour, ginger, cinnamon and sugar in a food processor, pulse to combine. Add butter and process until the mixture resembles breadcrumbs. Whisk golden syrup, egg and 3 tsp of water together. Add to the flour mixture and pulse until the dough just comes together, add more water if required. Turn onto a lightly floured surface and knead gently until smooth. Wrap in greaseproof paper and chill for 30 minutes.
Place a large flat tray in the oven. Preheat the tray and oven to 180°C fan forced. Remove one-quarter of the pastry. Roll out on a sheet of baking paper to 5mm thick. Cut Christmas trees or stars from the pastry to use for decoration, place on a tray and refrigerate until firm.
Roll remaining gingerbread out on a large sheet of baking to a 34cm circle. Use to line a 3cm deep, 26cm (base) tart tin, it should sit 1cm above the top of tin.
Peel and dice two of the mangoes and place into a bowl. Stir in the fruit mince. Spoon the mango mixture over the gingerbread base, leaving a 1cm border without filling. Fold the edge of gingerbread down to meet the filling. Decorate with gingerbread trees or stars. Place tart tin on the hot tray and bake for 25-30 minutes until golden. Set aside to cool. Remove tart from the tin.
Peel, chop and puree the remaining mango and swirl it through the cream. Dust the tart with icing sugar, cut into pieces and serve with mango cream.