Melt the butter. Crumble the rusk coarsely and put it in a freezer bag. Close the bag. Crumble the rusk finely with a rolling pin. Mix well with butter and coconut flakes. Line the bottom of a springform pan (26 cm Ø) with baking paper. Put crumb mixture on top and press to a firm base. Chill for about 1 hour.
Cut the vanilla pod in half lengthwise and scrape out the pulp. Boil up coconut milk, milk, sugar, vanilla pulp and vanilla pod in a large pot. Add rice and let it swell at low heat for about 40 minutes. Peel the mangos, cut the flesh from the stone. 2⁄3 Cut the mango into thin slices. Finely puree the rest of the mango.
Take rice pudding off the stove. Remove vanilla pod. Let the rice cool down for about 45 minutes. Remove crumb base from the pan and baking paper and place on a cake plate. Place the rim of the cake tin on top. Soak 4 sheets of gelatine in cold water. Whip cream until stiff. Squeeze out the soaked gelatine, dissolve at low heat and stir into the rice pudding. Fold in the cream.
Spread half the rice pudding on the cake base. Spread the mango slices evenly, slightly overlapping. Spread the rest of the rice pudding on top. Chill for at least 3 hours.
Soak 4 leaves of gelatine in cold water. Mix mango puree and orange juice. Squeeze the gelatine and dissolve at low heat. Stir in 4 tablespoons of mango puree, then stir into the rest of the puree. Spread on the cake and chill for at least 1 hour.
Roast the coconut chips in a pan without fat until golden brown. Let it cool down and decorate the cake with it.