To make the syrup , place the sugar and water in a medium saucepan.  Stir over a medium heat until sugar is dissolved.  Bring to the boil.   Add the lemon juice.  Reduce heat and simmer for 10 minutes without stirring.   Add the rosewater and simmer a further 2 minutes.  Remove from the heat and cool.  Refrigerate until chilled.

Combine all the nuts, sugar and cardamom in a bowl.

Cover the filo pastry with a damp tea towel, while working with 1 sheet at a time.  Brush a pastry sheet lightly with melted butter.  Fold the filo sheet into thirds lengthwise, (same as folding an A4 letter or brochure).

Brush the top with melted butter. Spread about a ¼ cup of the nut mixture evenly over the filo, leaving 1cm clean edge along one end to seal.  Starting from the opposite end roll up the pastry like a Swiss Roll and seal end with extra melted butter.  Keep rolls covered with a damp tea towel.  Repeat with remaining pastry and nut filling.

Place rolls on baking trays and brush tops with melted butter.  Bake for 10-15 minutes until lightly golden brown.  Reduce temperature to 140°C (120°C fan-forced) and continue baking for 30 minutes.  Set aside to cool completely.

Cut the rolls on the diagonal into 3cm lengths.  Transfer to a large ceramic dish with a cut side facing up.  Pour the cold syrup evenly over the pastries and leave to soak 6 hours or overnight.  Pastries can be stored in an airtight container for 4 days in a cool place (do not refrigerate).  The crispness will gradually decrease.