Preheat your oven to 350°F (175°C) and line a 9-inch springform pan with parchment paper. In a mixing bowl, combine cake flour, baking powder, baking soda, salt, granulated sugar, milk, neutral oil, and vanilla extract. Mix until smooth, about 3-5 minutes. Pour the batter into the prepared pan and bake for 15 minutes, or until the cake is lightly browned and a toothpick inserted comes out clean.

Once baked, remove the springform pan from the oven and allow the cake to cool in the pan for 5 minutes. Carefully transfer the cake onto a wire rack to cool completely, about 30 minutes.

To prepare the mango mousse, start by blooming gelatin in 2 tablespoons of cold water for 5 minutes. Meanwhile, blend the mango chunks until smooth to create a puree. Heat the bloomed gelatin in a microwave for about 10 seconds until dissolved, then mix it into the mango puree.

In a separate bowl, whip the cream with powdered sugar until firm peaks form, then gently fold both mixtures together until well combined, creating a light and airy mousse.

Pour the mango mousse over the cooled cake, spreading evenly with a spatula. Cover the springform pan with plastic wrap and refrigerate for at least 4 hours, or until the mousse is fully set.

For the mango curd, heat the reserved mango puree in a saucepan over medium heat. In a small bowl, mix granulated sugar and cornstarch into a slurry and add it to the warm puree. Stir continuously until thickened, about 5-7 minutes. Mix in unsalted butter until melted.

Allow the mango curd to cool slightly before pouring it over the set mousse layer. Swirl the curd over the mousse if desired.

Cover the assembled mango mousse cake again and chill for at least 12 hours or overnight for best results.