For the pie base:

Mix together the flour, salt. Cut butter into the flour and mix lightly until the mixture resembles coarse crumbs.

Beat egg, water and sugar lightly.

Mix the egg mixture in the flour and lightly form into a dough. DO NOT overmix.

Wrap the dough in a cling foil and allow it to harden it a bit in the fridge before rolling it out.

Dust the pastry on both sides with flour. On a lightly floured work surface, roll out the pastry to a round, about 1/6 inch thick. Carefully roll the pastry around the rolling pin and transfer to the prepared ring, pressing it into the corners.

Trim the overhanging pastry to 1 inch and press it firmly against the outside of the ring. Use the trimmings to fill any cracks. Refrigerate the shell for 20 minutes.

Preheat oven to 180 degrees. Line the pastry shell with a round of parchment paper or aluminium foil; fill the shell with dried beans or rice.

Bake the pastry for about 20-25 untill lightly browned around the edges.

Keep it aside to cool.

For the filling:

Making the caramel: Start with an even layer of all of the sugar in a pan.

Once the caramel starts browning at the edges, begin to drag the sugar towards towards the center to prevent any burnt spots. (very lightly) Do not over stir.

Keep stirring till you get a smooth liquid.

Stop the heat and immediately add butter to stop the sugar from cooking further.

Turn up the heat again and slowly pour the milk into the caramel and keep stirring till you get a smooth caramel sauce.

Turn off the heat. Mix the chocolate pieces in the caramel sauce immediately and keep stirring till the chocolate is melted. Mix in the vanilla.

Beat together the eggs and flour and slowly add in the caramel-chocolate mixture.

Stir in the chopped walnuts

Put the mixture in the half baked pie shell and bake for another 15-20 mins.

The pie will still be a little gooey in the inside but just set from the top.

Refrigerate until cooled and set. Serve.