Empty a pot of plain yoghurt into a mixing bowl and wash the pot so it can be used as a measure for the other ingredients. Mix together the yoghurt, 2 pots of sugar, 3 eggs, 3 pots of plain flour and 1 sachet of raising agent.
Pour the mango slices into a sieve and strain off the juice and set aside. Butter a cake tin and line the base with mango slices, pour the cake mixture on top of the mango and cook for 30 minutes at 350 F / 180 C. Allow to cool and then turn out onto a serving plate. Mix together 20cl of the mango juice with 1 teaspoon of rum and pour over the cake.