Pulse the graham crackers and almonds together in a food processor to make coarse crumbs. Don’t overly process; a few larger pieces of nuts are fine.
Transfer to a mixing bowl. Sprinkle with jaggery. Add melted ghee, stirring to combine.
Press crumbs into the bottom of an 8-inch spring-form pan using fingers or the back of a soup spoon or small drinking glass. Pack the crumbs tightly.
Bake for 8 minutes. Remove from oven; cool completely before adding the mousse filling.
Make the Mango Mousse
Using either a stand or hand-held mixer, whip the cream, gradually adding the sugar, until stiff peaks form. Gently fold in mango puree until completely combined. Transfer temporarily to the refrigerator.
Fill a small saucepan with 50ml cold water. Sprinkle gelatin evenly over the surface of the water. Let it stand for 5-10 minutes. Heat very gently, stirring until gelatin is completely dissolved. Cool to room temperature then stir it into the mango mousse (from the refrigerator).
Pour the mousse over the cooled crust in the cake pan, using a spatula to even out the top. Gently tap the pan flat down on the counter a couple of times to help settle the mousse.
Cover with plastic or other wrap; chill in the refrigerator for at least 4 hours, or until the mousse is completely set.
Make the Mango Gel Topping
Combine mango puree with sugar.
Put cold water in a small saucepan. Sprinkle gelatin evenly over the surface of the water. Let it stand for 5-10 minutes. Gently heat, stirring until gelatin is dissolved. Cool to tepid or room temperature. Pour over mango puree and sugar mixture, stirring to combine.
Pour over the cold mousse, spreading evenly over the top. Chill several hours or until the gel is completely set.
Add the Final Touches
Once cake is completely chilled, set it over a cake stand or platter. Using a knife around the edges if needed, loosen the mousse from pan, removing the sides.
Pat handfuls of coconut flakes around the sides of the cake.
Decorate the top with mango slices, coconut flakes and fresh mint leaves.