Preheat the oven to 180° C. Lay a baking sheet with parchment paper. Mix flour, baking and cacao powder and sieve through a fine colander. Add grated coconut, sugar, butter, egg and milk and mix to a fine dough. Spread the dough evenly on the baking tray and bake for 12 – 15 minutes.
Soak the gelatin in cold water for 10 minutes. Chop the chocolate. Heat coconut milk and dissolve gelatin in it. Add Rum and chocolate and allow to melt. Stir to a smooth, homogeneous mass. Whip the cream to a fluffy peak consistency; add grated coconut and fold it in the coconut-chocolate mass. As soon as the cream tightens, spread it over the chocolate cake. Sprinkle it with roasted grated coconut.