Preheat the oven to 180C/350F/Gas 4.
Place the butter, golden syrup, vanilla extract and sugar into a heavy-based saucepan over a low heat.
When the butter has melted, remove the pan from the heat and leave to cool for 5-10 minutes.
Add the beaten eggs to the mixture and stir well.
Set aside a small handful of the pecan nuts. Arrange the remaining pecan halves evenly in the pastry case and carefully pour over the syrup mixture.
Place into the preheated oven and bake for 40-50 minutes - the pie will be golden-brown, but the filling should still be slightly soft.
Leave the pie to cool on a wire tray. As the pie begins to set, decorate the top with the reserved pecan halves. Serve in slices.