Cake Layer
1-Prep: Prep: Preheat oven to 350°F. Line a 9″ springform pan with parchment paper on the bottom of the pan only by clamping it in between the bottom plate and ring of the pan. Set aside.
2-Mix batter: Mix batter: In a large mixing bowl, whisk together cake flour, baking powder, baking soda, and salt. Add the sugar, milk, oil, egg, and vanilla extract. Whisk together until combined into a smooth batter. Pour the batter into your lined springform pan.
3-Bake: Bake: Bake cake for about 15 minutes or until the sides are lightly browned and a toothpick inserted in the middle comes out mostly clean. Let the cake cool completely on a wire rack.
4-Prep cake and pan: Prep cake and pan: Once cooled, run an offset spatula around the edges of the cake to release it from the pan. If your cake is domed, you can remove it from the pan, use a serrated knife to level the cake, and put it back into the pan. Line the sides of the pan with a sheet of clear acetate or parchment paper. Set aside.

Mango Mousse
5-Bloom gelatine: Bloom gelatine: Fill a small bowl with cold water. Sprinkle gelatine powder on across the surface. Set it aside for at least 5 minutes to allow the gelatine to bloom. It will become a firm, gel-like consistency.
6-Make mango puree: Make mango puree: To a blender, add all of the mango chunks for both the mousse and the curd (900g in total) so that you only need to blend them once. Blend mangoes on medium speed for about 1 minute or until smoothly pureed. Transfer 400g of mango puree to a small saucepan and set aside to make the mango curd later. Keep the remaining 500g of mango puree in the blender.
7-Add gelatine: Add gelatine: Heat the bowl of bloomed gelatine in the microwave in 10-second increments until it completely dissolves and becomes a clear liquid. Pour this into the blender and blend for 30 seconds until combined with the mango puree. Set aside.
8-Whip cream: Whip cream: In a large mixing bowl, add the whipping cream and powdered sugar. Use a whisk to whip until it becomes firm peaks.
9-Fold in mango: Fold in mango: Add the mango-gelatine mixture from the blender and fold together until no streaks remain.
10-Fill pan: Fill pan: Pour the mixture into the springform pan on top of the cake layer. Gently jiggle the pan to help the mixture settle into a flat layer or use an offset spatula to smooth the top.
11-Chill: Chill: Chill the cake in the fridge while you make the mango curd topping.

Mango Curd
12-Cook: Cook: To the saucepan of mango puree you set aside earlier, add the sugar. Heat the mixture on medium heat, stirring often.
13-Cornstarch slurry: Cornstarch slurry: In a small bowl, stir together the cornstarch and water to make a slurry. Stir the slurry into the mango mixture. Continue heating the mixture, stirring often, until it thickens, about 10-15 minutes.
14-Stir in butter: Stir in butter: Remove the saucepan from the heat and stir in one cube of butter at a time until they have all melted and combined. Push the mango curd through a fine mesh sieve into a medium bowl to create a silky smooth curd. Press a piece of plastic wrap directly onto the surface of the curd and let it cool at room temperature or in the fridge until it thickens to a spreadable consistency.
15-Topping: Topping: Once the mango curd is cool to the touch, pour it on top of the chilled mousse layer which should be firm to the touch by now. Use the back of a spoon to spread the mango curd around the surface of the cake. Drag the spoon around the curd to create a swirl design.
16-Chill: Chill: Cover and chill the cake for 12 hours or overnight to allow it to set. Before serving, release the cake from the pan and peel away the acetate sheet. Decorate the top of the cake with mango chunks and mint leaves, if desired.