1. Prepare the ingredients in advance, as filo pastry starts to dry out as soon as the packet is opened.  
   Chop the walnuts roughly, without reducing them to a powder.  Add the cinnamon and pistachio nuts and mix well. 
   
2. Place a sheet of baking parchment on the baking sheet and butter well.  Melt the 100g butter in a small saucepan.  You will use the melted butter to brush each sheet of filo as you place it on the sheet. 
3. First of all place 3 sheets of buttered filo onto the baking sheet, raising up the edges slightly.  Sprinkle the prepared filling on top and cover with (1) a sheet of buttered filo, sprinkle the prepared filling on top of this and then repeat in a similar fashion, finishing with three sheets of buttered filo.  Before putting in the oven, cut the pastry into diamond shapes, cutting right through to the bottom sheet. 
   
4. Bake at 150 for 70 minutes until golden.
   
5. Meanwhile prepare the syrup.  Place all the ingredients into a saucepan and bring to the boil.  Boil for 8 minutes.
   
6. Pour the boiling syrup over the baklavas as soon as you take them out of the oven. 
   
7. Allow to cool for 24 hours.
   
8. Bon appétit!
   

The baklavas should keep for 4 days in a tin. 

Adapted from an original recipe by Dillou