To prepare Thandai Mousse, cut china grass sheet into small pieces and blend in the mixer to get a coarse powder. Transfer to a bowl and keep aside. 

For whipping the cream, transfer the cream to a large bowl. Using an electric hand blender at medium speed whip the cream till soft peaks are formed. Keep the bowl of whipped cream in the fridge while you prepare the thandai flavored mixture.  

In a small pan add milk, china grass and 1/2 cup of water. Heat pan over medium heat while stirring continuously the ingredients in the pan. Bring the mixture to the boil once, reduce the flame to low. Once pieces of china grass start dissolving in the liquid, add sugar. Stir to evenly combine.

Now add the thandai masala, stir the mixture with a spoon continuously. Bring the mixture to boil once and then let it simmer over medium heat for few minutes or till it start thickening. 

Once liquid start thickening, turn off the heat. Arrange a metal strainer over a large bowl. Strain the hot mixture into the bowl. You will notice all the undissolved pieces of china grass remain in the sieve. 

Transfer the strained mixture into a steel bowl and place the bowl in a deep vessel filled with ice cubes for 8 to 10 minutes or until the mixture cools down. Whisk the mixture vigorously and continuously till it is in ice-cube vessel to avoid any lump formation.Add the beaten whipped cream and fold gently.Add the lemon juice and fold gently.

Now gently fold in the whipped cream into the thandai flavored mixture. Once the whipped cream and the liquid is evenly combined, add the lemon juice. Stir gently once to combine the lemon juice. 

Transfer equal portions of mousse into the serving bowls. Refrigerate the mousse for about 6 hours or overnight to have it set perfectly.

Garnish Thandai Mousse with chopped pistachio before serving. 

 Serve Thandai Mousse as a dessert along with a quick snack of Corn Matar Kachori this festive season.