Grease a 23cm pie tin with the melted butter.

Place the flour, caster sugar and butter in a food processor and blitz until it resembles bread crumbs.

Add the water and process just until the pastry comes together.

Scoop it all into your hands and shape into a smooth ball then flatten into a disc and wrap in plastic wrap.

Refrigerate the dough for 30 minutes to 1 hour or until well chilled.

Roll the dough out between two sheets of baking paper until it is 5mm thick and a round shape.

Use the rolling pin to lift the pastry over the tin and line it, cutting off any excess and using it to fill and gaps. Pinch the edges to crimp if your tin is not fluted.

Cover with plastic wrap and chill again for 30 minutes.

Meanwhile, pre-heat the oven to 180C (390F) fan-forced.

Lien the pastry case with baking paper and fill with pie weights (I use dried beans which I keep in a container in the fridge).

Bake for 10 minutes.

Remove the paper and the weights and bake another 10 minutes or until lightly golden.

Meanwhile, make the brownie filling.

In a microwave-proof bowl, combine the butter and dark chocolate and microwave, 20 seconds at a time, stirring well between each heating, until smooth.

Set aside to cool slightly.

In a large bowl, whisk the eggs a little then stir in the sugar, flour and vanilla.

Carefully stir through the melted chocolate then fold in the chocolate chips.

When the pastry case is cooked, remove it from the oven and turn the temperature down to 160C (350F).

Place the salted caramel sauce in a small microwave-safe dish and microwave for 10 seconds or until a bit runny.

Pour the brownie batter into the pastry shell.

Drizzle the salted caramel sauce over the top in lines. Use a knife to draw lines in the sauce in the opposite direction alternating the side you start on.

Bake the pie for 35 to 45 minutes or until the brownie is puffed and starting to crack.

Transfer to a wire rack to cool completely.

To serve, heat the pie in the tin in a 160C fan-forced (350F) oven for 10-15 minutes.

Dust the pie with icing sugar and serve with cream or vanilla ice-cream and an extra drizzle of salted caramel sauce if so desired.