For the wontons
For the syrup
Preheat the oven to 180°C/350°F/Gas mark 4. Lightly grease a 25cm/10in loose-bottomed cake tin.
Mix together the walnuts, sugar and cinnamon in a bowl.
Unfold the filo pastry, and cover with a damp tea towel to prevent it drying out. Brush a piece of the filo with melted butter, and fit it into the bottom of the tin with the buttered side down. Let the edges spill over and brush with butter. Repeat with three more buttered filo sheets, making sure that the whole tin is lined.
Sprinkle with half of the nut mixture. Repeat with four more layers of buttered filo, then scatter the remaining nut mixture over them. Put two more layers of buttered filo on top, then fold the edges in and under.
Cut the last two pieces of filo so they that fit the tin, place on top and brush generously with butter. Bake for 40 minutes, then increase the temperature to 200°C/400°F/Gas mark 6. Bake for a further 20 minutes or until golden brown.
To make the syrup, gently heat the lemon juice, sugar and cinnamon until the sugar has dissolved and the syrup has reduced slightly. Pour over the cooked baklava, and leave to cool in the tin for 1–2 hours. Cut into wedges and serve.