To make the pastry: Sift flour and salt into a mixing bowl. Cut the butter into small cubes and add into the flour. Using your fingertips, rub butter into flour until the mixture resembles fine breadcrumbs.
Stir in sugar. Make a well in the centre and pour in the lightly beaten egg and vanilla essence. Slowly work the mixture together using a palette knife. (if dough is too dry, sprinkle with water until the pastry just holds together.)
Remove the dough from the bowl onto a lightly floured surface or table top. Knead lightly until smooth.
Pat into a ball and wrap in cling film. Chill in the refrigerator for about 20 minutes before use.
Grease a 22cm round, loose-base flan tin. Roll out pastry between sheets of baking paper until it is large enough to line the prepared tin. Lift pastry into tin, ease into the sides and trim the edge neatly. Lightly prick the base with a fork; refrigerate for 30 minutes.
Cover pastry with baking paper and fill with dried beans. Bake in a preheated oven at 190 ºC for 10 minutes. Remove paper and beans and bake for a further 10 minutes or until lighly browned. Cool.
To make the filling: Beat the eggs in a bowl and add salt, melted butter, corn syrup, sugar and vanilla essence. Mix well to combine.
Sprinkle the chopped walnuts over the bottom of the baked pastry case. Pour filling over. Bake in a preheated oven at 160 ºC for 40 to 50 minutes or until the filling has just set. (if the filling puffs up too much, reduce the temperature to 150ºC.)
Leave the pie in the flan tin for five to 10 minutes or until it is cool enough to handle before removing it to a wire rack to cool completely.