For this dessert, we rely upon caramel flavor to shine in the mousse. The flavor tastes best when dessert is chilled. (The dessert does not freeze rock hard in the freezer. It gets an ice cream-like texture upon freezing.)
Put the biscuits into a food processor and grind them into fine crumbs. Mix in butter and transfer the mixture to a dish. Level the base with the base of flat glass. Place in the fridge to harden. Protip: For individual servings divide the mixture in 8-10 glasses.
In a large bowl, whip cream with a beater until you see stiff peaks.
Mix dulce de leche and vanilla essence in whipped cream with a beater. Protip: The dulce de leche will slowly melt in the cream so beat it at intervals if dulce de leche is thick.
Next, whip the egg whites with a beater until you see stiff peaks. Mix in egg whites with a spatula just until combined. Set aside.
Bloom gelatin by mixing gelatin with warm water. The gelatin crystals should dissolve completely. Mix gelatin in the mousse with a spatula.
Pour mousse filling over the chilled biscuit crumbs.
Cover the mousse with cling wrap and let it sit for at least 4 hours in the fridge before adding the sauce.
Make a thin layer of salted caramel sauce on the mousse. Protip: If using homemade sauce, make sure the sauce is slightly warm for easy spreading.
Garnish with biscuit crumbs. Cover with cling wrap again and chill.
Notes
Dulce de Leche: To make homemade dulce de leche, take a can of sweetened condensed milk, remove the wrapper. Fill a large pot with water and place the can in it. Water must be 1-2 inches above the can. Boil the can for 3.5 hours. Do Not open the can until absolutely cooled. Wait for at least after 4 hours, or preferably let it cool overnight. Find my detailed recipe here.Egg whites: Egg whites help lift the mousse and make it light. But if you dislike raw eggs in a dessert, you can skip them. Gelatin: Gelatin helps in setting but you can skip it, let the mousse set for 8 hours in the fridge and chill in the freezer for 30 minutes before serving.Serving Variation: You can make this dish as a mousse cake in a removable base pan too. In that case, do not skip gelatin.