Combine milk and cornflour in a heavy sauce pan. Blend in beaten eggs, 1/2 cup sugar and pinch of salt. Place over medium heat and stir constantly until thickened and bubbling. Remove from heat, stir in vanilla essence. Cover top of custard with buttered wax paper to prevent a skin forming.
Place Kataifi pastry in a large bowl and gently separate strands with fingers. Grease a 8 x 11 inch oven dish with some of the butter. Put half the Kataifi in the base, pressing it down to make it compact. Drizzle 1/4 cup butter evenly over it. Pour custard filling over Kataifi, spreading it evenly. Top with remaining Kataifi. Spread evenly and pat down gently.
Pour remaining melted butter evenly over top. Bake in a pre-heated 375°F oven for 45 minutes until golden brown. Remove from oven and leave until cool.
Meanwhile; dissolve the remaining sugar in water over medium heat. Add lemon rind and cinnamon stick and bring to the boil. Add lemon juice and boil over medium heat for 15 minutes, skimming when necessary. Do not stir once syrup is boiling.
Strain hot syrup over cooled pastry. Leave until cold and cut into diamond shapes to serve.