Preheat the oven to 350°F (175°C) and grease a 9-inch round cake pan.

In a large bowl, sift together the flour, baking powder, baking soda, and salt.

In a separate bowl, whisk the eggs and granulated sugar until light and frothy.

Add the vegetable oil, 3/4 cup of the mango puree, milk, and vanilla extract to the egg mixture, whisking until combined.

Gradually add the dry ingredients to the wet ingredients, stirring until the batter is smooth.

Pour the batter into the prepared cake pan and bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.

Cool the cake in the pan for 10 minutes before transferring to a wire rack to cool completely.

In a chilled bowl, whip the heavy cream and powdered sugar until stiff peaks form.

Fold the remaining 1/4 cup of mango puree into the whipped cream.

Spread the frosting over the cooled cake and garnish with fresh mango slices before serving.