To begin with Thandai Mousse Cake, preheat the oven at 180 degree celsius.

Line a 8 inch round cake pan with parchment paper, grease the sides and keep it aside.

In a mixing bowl sift dry ingredients for the cardamom sponge cake - flour, baking powder, baking soda, mix well and keep it aside.

Take another mixing bowl, add in oil, sugar, curd, vanilla essence, cardamom powder and mix well using a hand whisk or electric beater.

Now, fold in the dry mixture into the wet cake mixture little by little, use a spatula to fold in, do not over mix. 

Once the batter is ready, transfer it into the lined pan and bake the cardamom sponge cake for around 25 minutes at 180 degree celsius or until a skewer inserted in the centre of the cake comes out clean.

When the cardamom sponge cake is done, let it cool for 10 minutes within the pan, then demould the cake and let it cool on a wire rack. 

Meanwhile prepare the Thandai mousse, chop white chocolate and place in a bowl.

Now take a small saucepan and bring the fresh cream to a boil on a low flame.

Pour the hot fresh cream on the white chocolate and let it sit for few mins, then using a spatula, stir the mixture and mix well until the chocolate completely melts and you get the ganache.

Keep the ganache to cool down, meanwhile beat the heavy whipping cream to stiff peaks.

When the ganache fully cools down, add in the thandai syrup and mix well.

Once it is done, start adding whipped cream to the white chocolate thandai mixture and fold lightly using a spatula. Be gentle and fold without deflating any air from the whipped cream.

To assemble, take a 8 inch/20 cm round springform pan and place the prepared cake into it.

Now top the cake with prepared mousse mixture and tap it so that the mixture settles. Smoothen the top with an offset spatula.

Garnish the Thandai Mousse Cake with chopped almonds, pistachios, saffron and keep in the refrigerator.

Chill the mousse cake for four to five hours, preferably overnight.

Once you are ready to serve, loosen the sides using a knife and demould the cake.

Serve Thandai Mousse Cake as an indian dessert for your parties like Holi or Diwali.