Chocolate Nutella Dulce de Leche Mousse Cake

This is the birthday cake I made for my nephew, I do not want to make him a usual chocolate mousse cake so I combined both recipes that I had used before and came out this.

Ingredients : for 7" cake
For Base:
80gm oreo cookies - blended
30gm butter - melted

Mix all the biscuit base ingredients together and press into a 6" springform tin. Baked at preheated oven at 200C for 10 mins and cool aside then chill in the refrigerator while preparing the filling.

Dulce De Leche Mousse : Adapted from here
200ml whipping cream, cold
100g dulce de leche, cold
1 tsp gelatin
1 tbsp water

1. Measure water into a bowl and sprinkle in the gelatin (without stirring with a spoon). Set aside to allow the gelatin grains to swell (10 mins) before setting the bowl over a pot of simmering hot water. Stir with a spoon and once the gelatin melts, remove the bowl from the pot and set aside to cool to room temperature.
2. Put dulce de leche into mixing bowl and put in a bit of cream. On low speed, mix to combine, adding more gradually. When all the whipping cream has been added in, turn to high speed and beat until soft peaks.
3. Turn to low speed. Add in gelatin mixture slowly while beating, and beat until stiff.

For Nutella Chocolate Mousse : adapted from here
1 egg yolks
15g sugar
40g melted butter
50g dark chocolate
100g nutella
150ml whipped cream
1 tsp gelatin powder + 1 tbsp water

Method :
1. Measure water into a bowl and sprinkle in the gelatin (without stirring with a spoon). Set aside to allow the gelatin grains to swell (10 mins) before setting the bowl over a pot of simmering hot water. Stir with a spoon and once the gelatin melts, remove the bowl from the pot and set aside to cool to room temperature.
2. Melt dark chocolate and nutella over a pot of simmering hot water and stir till mix well and set aside to cool down to room temperature.
3. Whisk the egg yolk and sugar on a double boiler until pale in color and thicken. Mix in the melted butter.
4. Add the melted dark chocolate & nutella to the egg yolk mixture, mix until well combine.
5. Add in the gelatin solution and mix well.
6. Fold in the whipped cream into the chocolate mixture.

Chocolate Ganache Topping :
100g chocolate, chopped
60g whipping cream
20g butter

1. Boil the chocolate, whipping cream and butter until mix well and smooth. Set aside for cool slightly.

Assembly :
1. Alternate scoop the DLL mousse and Nutella Chocolate Mousse onto the cookie base until fill up 3/4 of the cake tin. Left one cup of DLL mouse for decoration purpose if desire.
2. Chill the mousse cake in the fridge and about 4 hours.
3. Bring the mousse cake out from the fridge and unmould the cake.
4. Pipe the DLL mousse at the edge of the cake and pour in the chocolate ganache and chill the cake until serving.