To make the base, place the biscuits into a bag, and use a rolling pin to bash them until they resemble breadcrumbs.
Alternatively, add them to a food processor, and blitz until they are a fine texture.
Melt the butter, then add it to the bowl together with the crushed biscuits, and mix well.
Place the mixture into a round baking tin that has either detachable walls or removable bottom, and press down firmly making sure it is spread into an even layer.
Chill in the fridge for at least 30 minutes.
To make the filling, place the gelatine granules into a small bowl, add 5 tablespoons of warm water, and mix well.
Set aside for 15 minutes.
Place the double cream into a pan, and bring to the boil.
Remove from the heat, add the gelatine to the pan, mixing well in order to dissolve it completely.
You can now add the sour cream, mascarpone and nutella.
Separate the egg yolks from the egg whites.
The egg yolks will be beaten with the sugar and added to the other ingredients, and the egg whites be will beaten until they hold stiff peaks.
Once you get a meringue-like consistency, gently fold the egg whites into the nutella mixure.
Pour it over the biscuits base and transfer it back to the fridge to chill, ideally overnight or for at least 6 hours.
To make the glaze, mix the gelatine granules with 5 tablespoons of warm water, and set aside to hydrate for 10-15 minutes.
Pour the double cream into a pan, bring it to a boil, then add the cocoa powder, icing sugar and chocolate broken into pieces, and stir well until you get a smooth consistency.
Remove from the heat, add the gelatine and whisk well to disolve it.
Pour the glaze over the chilled cheesecake, then leave to set for a further one hour.
Decorate with slices of strawberries or any other fruit. Serve cold from the fridge.