Prepare a 23 cm round cake tin, grease it and preheat the oven to 175 °C.
Whisk the flour, baking powder, baking soda and salt in a medium bowl.
In a large bowl, mix the softened butter and sugar until light and fluffy. You can use an electric mixer or do it by hand.
Add the eggs, one at a time, beating well after each addition. Add the mango puree to the butter and sugar and mix until well combined.
Gradually add the dry ingredients to the mango mixture, alternating with the buttermilk. Start and finish with the dry ingredients. Stir until all the ingredients are combined. Stir in the chopped mango, if desired, to add texture to the cake.
Pour the batter into the prepared cake pan and smooth the top with a spatula.
Bake in the preheated oven for about 35-40 minutes or until a toothpick inserted in the centre comes out clean. When the cake is baked, take it out of the oven and leave it to cool in the baking tray for 10 minutes. Then transfer the cake to a wire rack to cool completely.
Once the cake has cooled, spread the icing over the cake and garnish with sliced mangoes to bring out the mango flavour even more.