In a medium bowl, mix together the pecans, 1/3 cup sugar, 65g butter and 1/2 cup chocolate chips. Press into the bottom and up the sides of a 23cm pie plate. Bake for 8 to 10 minutes in the preheated oven. Cool completely.
In a metal bowl set over a pan of simmering water, combine 1 1/3 cups chocolate chips and 125g butter. Stir occasionally until melted and smooth. Remove from the heat and stir in the vanilla.
In a separate bowl, beat egg yolks with 1/4 cup sugar until thick and pale using an electric mixer, at least 3 minutes. Stir into the melted chocolate and set it back over the pan of simmering water. Whisk constantly until thick, 3 to 4 minutes. Pour into the cooled crust and smooth the top.
Heat the heavy cream in a small saucepan. When warm, stir in the remaining chocolate chips until melted. Remove from the heat and stir in the brandy. Pour over the filling. Refrigerate for several hours to set before serving.