Preheat the oven to 180º C.
To make the filling, beat the egg white till soft peaks.
Mix together the cream cheese and sugar till creamy. Add the beaten egg white and fold well.
To make the batter, sieve together the flour, baking powder and salt into a bowl. Mix.
Cream together the butter and sugar in another bowl till light and fluffy. Add the egg, egg yolk and vanilla essence and mix well. Add the flour mixture and sour cream and fold well.
Pour the prepared batter into eight individual silicon muffin moulds and smoothen with a spatula. Spread the filling on top and place the mango cubes on top.
To make the streusel topping, combine the sugar, flour and butter in a bowl. Mix well.
Sprinkle the streusel topping on top of the mango cubes. Put the moulds in the preheated oven and bake for forty to forty-five minutes. Remove from oven, cool and demould.