In a small bowl, pour gelatin with 100 ml warm water and set aside.
Then grind the cookies. Melt butter and mix with cookies crumbs. Pour mixture into 24 - 26 cm tray and press a little with spoon or your hands. Put in refrigerator.
Dissolve gelatin. In another bowl, beat cream with sugar, add mascarpone and mix very well. Add gelatin and mix to combine. Pour filling onto the crust, smooth a little and season with some grated dark chocolate. Put in refrigerator for 3 - 4 hours.