Place the hazelnuts and almonds on a lined baking tray and put them in an oven at 180°C for 5 to 10 minutes, stirring every couple of minutes to get them evenly roasted. Remove from the oven and allow to cool.
Remove the pistachio nuts from their shells. Roughly chop up the nuts and the shortbread biscuits, you want them to be quite chunky, and set aside.
Chop up the chocolate evenly and place in a bowl, heat the cream until it’s just about to boil, then pour over the chocolate and stir well until all the chocolate has melted and the mixture is smooth. Add the chopped nuts and biscuits to the ganache and mix well.
Place a few sheets of cling wrap on top of each other, you want to have a few wrinkles and creases so it adds to the overall look at the end.
Spoon out the chocolate mix onto the cling wrap, about a third of the way in along the longest side, leaving room on both ends. Roll tight and tie one end, then tighthen the roll again, and tie the other end.
Place in the fridge for a couple of hours, or overnight. Once set remove the cling wrap and roll in icing sugar.