Preheat the oven at 175 degrees Celsius.
Make the graham biscuits in to crumbles.
Melt the butter in a casserole, and mix it with the biscuit crumbles.
Cover the bottom and the edges of a small pie form with the pie crust.
Place it in the middle of the oven for 10 minutes. Take out the pie crust and let it get cold.
Whip the heavy cream to a hard foam in a bowl.
Mix the cream cheese soft with an electrical mixer. Mix it with 2/3 of the hazelnut chocolate cream.
Stir the heavy cream and the cheese cream mixture together so you will get a hard foam. Place the mousse in the fridge until the pie crust is cold.
Spread evenly the rest of the hazelnut chocolate cream on top of the crust bottom, and after spread the mousse on top of it. Place the cheesecake in the fridge for minimum 2 hours before serving it.