Cake Layer
Preheat oven to 350°F (175°C). Line the bottom of a 9-inch springform pan with parchment paper.
In a large bowl, whisk together cake flour, baking powder, baking soda, and salt.
Add sugar, milk, oil, egg, and vanilla extract. Mix until smooth.
Pour batter into the prepared pan and bake for about 15 minutes, or until a toothpick inserted into the center comes out mostly clean.
Let the cake cool completely on a wire rack.
Run a spatula around the edges to release the cake. Level the top if needed and return cake to the pan.
Line the sides of the pan with acetate or parchment paper.
Mango Mousse
In a small bowl, sprinkle gelatine powder over cold water and let bloom for 5 minutes.
Blend all mango chunks (900 g total) until smooth.
Transfer 400 g mango puree to a saucepan for the curd and keep the remaining puree in the blender.
Melt the bloomed gelatine in the microwave in short intervals until liquid, then blend into the mango puree.
In a separate bowl, whip the cold whipping cream with powdered sugar until firm peaks form.
Fold the mango mixture into the whipped cream until smooth and fully combined.
Pour the mousse over the cake layer and smooth the top.
Refrigerate while preparing the mango curd.
Mango Curd Topping
Heat the reserved mango puree with sugar in a saucepan over medium heat.
Mix cornstarch and water to form a slurry, then stir it into the mango mixture.
Cook for 10–15 minutes, stirring often, until thickened.
Remove from heat and stir in butter cubes until melted and smooth.
Strain the curd through a fine mesh sieve for a silky texture.
Let cool until spreadable.
Assemble
Spread the cooled mango curd over the chilled mousse layer and create swirls with the back of a spoon.
Cover and refrigerate for at least 12 hours or overnight until fully set.
Remove from the pan, peel away the acetate, and garnish with fresh mango chunks and mint leaves if desired.