Grease a 10 inch baking pan with oil or melted butter, preheat oven to 350 degrees F/180 degrees C.
Mix one third (1/2) cup of melted butter with 1/2 cup of sugar then spread mixture to coat the bottom of the baking pan.
Arrange mango slices over the butter and sugar coating. They should be tightly packed, leaving no space in between.
Make the cake batter. In a large bowl, mix together melted butter, sugar, milk and vanilla extract. Add in eggs and mix well. Then add in flour, baking powder, salt and whisk together to form a smooth batter.
Pour batter into prepared baking pan and smoothen the top with a spatula.
Bake in prepared oven for about 50 minutes until it is golden brown ontop and a toothpick inserted in the middle comes out clean.
Turn cake upside down and serve!
Notes
1. You may want to reduce the sugar content of the batter to half or a quarter cup if you do not have much of a sweet tooth,