In a medium sauce pan whisk together flour, sugar (1 cup) ,cornstarch and salt
Slowly stir in water, lemon juice and the lemon zest. Bring to boil.
In a separate bowl whisk egg yolks ,take a little of hot mixture and whisk into eggs , when they are well mixed, Stir egg mixture into boiling lemon mix. Stir continually until thickened
Remove from heat and pour into pie crust
Meringue
In stand mixer or glass bowl beat egg whites until frothy
Slowly add the sugar and continue to beat until stiff peaks form.
Spread meringue over hot filling ,seal edges with meringue