Grease a round springform pan (28 cm) with a little butter.
Place the biscuits in a food processor and grind them finely, or crush them in a bag using a rolling pin. Melt the butter over low heat or in the microwave, then mix it with the crushed biscuits and the coconut until you get a uniform mixture with a wet sand texture. Evenly press the mixture into the base of a springform pan. Refrigerate until ready to use.
Soak the gelatin sheets in cold water. Peel the mango, cut the flesh into cubes and blend until you obtain a smooth purée. Reserve a few teaspoons of the purée for topping and set aside. Once the gelatin sheets have softened, remove them and dissolve in a small pan over very low heat or in a bain-marie, stirring continuously until liquid and smooth.
Add the gelatin to the mango in the blender and mix for a few seconds until combined.
Add the sugar and cream cheese to the mango purée, then blend until smooth.
Pour the cream over the biscuit base, then add small amounts of the reserved mango purée. Using a toothpick, gently create decorative swirls in the cream. Refrigerate overnight until set.