For the syrup, dissolve 120g sugar in 150ml water over a medium heat. Bring it to the boil, then add 60ml (¼ cup) honey, 1 stick of lemon grass, sliced lengthwise, and 4 juniper berries. Boil gently until the mixture has reduced to the consistency of a runny syrup, about 20 minutes.
Remove from the heat and set aside. Preheat the oven to 180°C. Lay out a sheet of phyllo pastry and brush the surface with 10ml (2 tsp) melted butter. Top with another sheet of phyllo pastry and brush the surface with 10ml (2 tsp) butter. Cut the pastry into the desired size. Place a small roasting grid in a baking tray and drape the pastry over the grid to get a corrugated effect.
Combine 50g roughly chopped walnuts, 50g roughly chopped almonds, 10ml (2 tsp) sugar, 10ml (2 tsp) ground cinnamon and 5ml (1 tsp) ground ginger in a bowl. Sprinkle the mixture over the pastry. Repeat until the nut mixture has been used up. Bake until golden, about 10 minutes. Pour the syrup over and serve.
Phyllo can dry out very quickly if left open. Cover the unbuttered phyllo sheets with a damp kitchen towel while working to stop them from drying out. Store any unused phyllo tightly wrapped in plastic in the fridge.