Preheat oven to 350 degrees Fahrenheit.
In a large bowl, mix flour, confectionary sugar, salt, and melted butter. Pour into a well greased or parchment lined 9 x13 baking dish. Bake for 20 to 25 minutes. Remove from the oven and leave to cool for a bit. Leave the oven on.
In a medium sized bowl, sift the sugar, flour, and pinch of salt.
In another bowl, whisk the eggs just until blended. Add the sugar mixture, blend, then the lemon juice and zest. Mix thoroughly until smooth and spread over the warm pastry.
Bake for 20 to 25 minutes. Remove from oven and cool completely.
Sift confectionary sugar over the top and cut into 10 rectangles.