Preheat your oven to 350°F (175°C). Line a 9" springform pan with parchment paper.

In a large mixing bowl, whisk together cake flour, baking powder, baking soda, salt, and sugar until well combined.

Add milk, oil, egg (or flaxseed egg), and vanilla extract. Mix until smooth.

Pour the batter into the prepared pan and bake for 15 minutes or until a toothpick comes out clean.

Cool completely in the pan on a wire rack.

To prepare mousse, bloom gelatin in cold water, then gently heat until dissolved.

Blend mango chunks until smooth and mix in dissolved gelatin.

Whip cold cream with powdered sugar until stiff peaks form, then gently fold into the mango mixture.

Pour the mousse over the cooled cake and chill for 4-6 hours until set.

For the mango curd, combine mango puree and sugar in a saucepan; thicken with a cornstarch slurry and stir in butter.

Spread mango curd over the set mousse layer and create a decorative pattern if desired.

Cover and refrigerate for at least 12 hours before serving.