Custard: In a medium saucepan, warm the milk and lemon peel. Bring to a boil and set aside.
In another medium pan, melt the butter and stir in the semolina, mixing until well combined.
Remove the lemon peel from the milk and discard it, then gradually pour the milk into the semolina, mixing well until thoroughly blended without lumps.
Next, add the sugar and bring the mixture to a gentle boil. Remove from the heat and set aside. Cover with heat resistant cling film to stop a skin forming and leave to cool slightly.
Preheat the oven to 180°C fan / 400°F / Gas 6 and grease a glass or ceramic 25cm pie dish with some melted butter.
Brush a filo sheet with butter and pull the two long sides towards each other in a pleated pattern.
Twist it into a snail shape and place it in the centre of the prepared dish.
Brush another filo sheet with butter and bring the long sides together again in a pleated pattern and coil it around the pastry in the centre. Repeat with the remaining butter and filo until you have filled the dish. Place the pie dish into the oven for 15 minutes until the filo is nice and golden. Meanwhile finish the custard.
In a mixing bowl, beat the egg and egg yolk with the vanilla. Add this to the custard and mix well to combine.
Once the filo is baked remove from the oven and pour the custard over the top into all the crevasses.
Baking: Place it back in the oven for 18-20 minutes until the top is golden brown and the custard has puffed up.
Remove from the oven, sprinkle with the icing sugar and cinnamon while hot, and allow it to cool for at least 10 minutes before serving.