Mix flour, grated coconut and baking powder. Cream butter and sugar with the whisk of the hand mixer. Stir in the eggs one by one. Add the coconut milk and flour mixture and mix to a smooth dough.
Pour the dough into a greased, flour-sprinkled box form (30 cm long), spread the jam on the dough by the spoonful, strum it coarsely and smooth it down. Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 1 hour.
Take the finished cake out of the oven, let it rest in the mould for about 10 minutes, turn out of the mould and let it cool down. Chop the chocolate and melt over a warm water bath. Spread the chocolate unevenly on the cake and let it set.