Method For Sponge:

1. Preheat the oven to 180C (OTG mode: upper rod + lower rod + fan). Grease two 6-inch round cake tins with oil and line them with butter paper. 
2. Sift together all-purpose four, corn flour, baking powder, and baking soda in a bowl.
3. In another bowl, cream together melted butter and icing sugar.
4. Add vanilla essence to the creamed mixture and mix.
5. Add in the sifted dry ingredients and mix well.
6. Now add buttermilk in parts. Combine everything well and make a smooth batter.
7. Pour the batter into the prepared tins equally.
8. Bake in preheated oven at 180C (OTG mode: lower rod only) for 30-40 minutes or until a toothpick inserted in the center comes out clean.

Method For Mango Curd:

1. Heat mango puree, lemon juice, sugar, and salt in a saucepan.
2. Meanwhile, in a small bowl, make a cornstarch slurry by mixing cornflour and water.
3. When the mango puree starts boiling, add the cornstarch slurry and cook until it gets thick.
4. Remove from heat, then add soft unsalted butter and mix. 
5. Transfer it to a bowl and let it cool down.

Method For White Chocolate Mousse

1. In a bowl, melt white couverture chocolate, set aside, and let it cool down.
2. In another bowl, beat whipping cream till soft peaks.
3. Now add in the melted white chocolate and beat again until combined properly.
4. Transfer it to a piping bag.

Method For Soaking Syrup:

1. Mix mango juice and water together.

Assembly:

1. Demould the songs and divide them into two parts with a cake leveller.
2. Now, on the cake base, pipe some mousse and spread it using a palette knife.
3. Place a sponge layer, then soak with soaking syrup using a pastry brush.
4. Pipe white chocolate mousse and smooth it out; pipe around the edges as well.
5. Now, pipe some mango curd in the centre and smooth it out.
6. Place another layer of sponge and repeat the same process as before until we get four layers of sponges
7. Now, pipe a thin layer of mousse all over the cake to crumb coat the cake.
8. Smooth it out with a palette knife and remove the excess with a metal scrapper.
9. Now, keep it in the freezer for 15=20 minutes.
10. Pipe a thick layer of mousse all over the cake and smooth it out.
11. For the top, add some mango curd in the centre of the cake and, using a palette knife, smooth it out.
12. Now, pipe some dollops of mousse around the mango curd using a round nozzle. Place few mint leaves randomly around the dollops.