Chocolate-Pecan Chess Pie

Dark, rich and very chocolate-like, this is our favorite new version of the pecan pie. Make it even more special and serve it with sweetened whipped cream.
Preheat the oven to 350 degrees. On a lightly floured surface, roll out the cake into a 13-inch circle. Place on a 9-inch pie dish; fold in the edges and crimp.Heat the butter and chocolate squares in a large, microwave-safe bowl at MEDIUM power (50%) for 1 1/2 minutes or until they are melted and smooth, stirring at 30-second intervals. Whisk together the condensed milk, eggs, and 1 teaspoon vanilla.Combine the granulated sugar and the following 3 ingredients. Add the sugar mixture to the chocolate mixture, whisking until smooth. Pour the mixture over the prepared cake.Bake the cake at 350 ° C for 40 minutes. Combine the pecans, the next 2 ingredients, and the remaining 1 teaspoon vanilla; sprinkle over the pie. Bake for another 10 minutes or until cooked through. Remove from the oven to a wire rack and allow to cool completely (about 1 hour).