Preheat oven to 160C/140C Fan/Gas 3 and line a baking tin (approx. 25 X 35cm) with parchment paper.
In a large bowl combine a pinch of salt and all the filling ingredients. Using a pastry brush, grease the parchment paper with butter to prevent sticking. Cut the sheets of filo so they’re the same size as the tin, then cover with a damp, lint-free tea towel to prevent them from drying out.
Press one sheet of filo pastry into the tin and brush with the melted butter. Continue to layer the pastry in this way until you have used up one pack of pastry. Off cuts of pastry can be used to make up the layers (around 10). Evenly spread the mincemeat mixture over the surface, then continue to top with the remaining pastry, brushing the layers with melted butter as you go. Brush the final layer generously with melted butter. Using a sharp knife, cut deep lines horizontally and vertically to form small squares. Bake for one hour until golden.
While the baklava is baking, make the syrup. Add the sugar, cinnamon sticks, orange rind and 100ml water to a saucepan and cook over a low heat until the sugar has dissolved. Simmer until the syrup is thick enough to coat the back of a spoon. Juice the reserved orange into the syrup.
Once the baklava has baked, remove from the oven and increase the temperature to 180C/160C Fan/Gas 4. Pour the syrup over the baklava, then return it to the oven for 5 minutes or until the syrup has been absorbed. Leave to cool completely in the tin, then slice into pieces along the cut lines.