If making your own crepes, set them aside once made and allow them to cool.
In a large bowl, whisk your heavy cream until you have soft peaks. Add the mascarpone and icing sugar. Continue to whisk until you have stiff peaks and the mascarpone is incorporated.
Place your first crepe on your cake stand or desired serving platter. Spread a thin layer of cream all over, being sure to spread the cream right to the edge so you can see it when topped with another crepe. Place another crepe on top and repeat with the cream and other crepes until you have your “cake”.
In the microwave or in a small saucepan, heat the nutella until it is drizzling consistency. Drizzle all over the top of the cake in a any pattern you like. You can serve immediately or keep in the fridge until ready to serve.