In a medium-sized mixing bowl, stir together the flour, cornstarch, and salt. Cut the cold, cubed butter into the flour mixture using a pastry cutter until the butter pieces are no bigger than peas. Add ice water, starting with 1-2 tablespoons and adding up to 3 in total or just until the dough starts to hold together when pinched. Turn onto a counter and form together into a disk with your hands. Generously flour the counter and the top of the disk of dough and begin to roll out into a circle about 12 inches in diameter.

Transfer the 12-inch round of dough to an ungreased 9-inch pie pan. Gently work out any air pockets and form the dough to the bottom and sides of the pan. Fold the excess dough from the edges to form a thick edge and style/crimp as desired. Coat the bottom and sides of the pie crust with a generous coat of flour (This helps prevent the crust from going soggy). Cover and chill in the freezer for 30 minutes or refrigerate for 1 hour.

Preheat the oven to 375℉. Take the chilled crust out of the freezer and cut a piece of parchment paper into a 12-inch diameter circle. Mold the parchment paper into the pan on top of the crust. Fill the lined pan almost to the top with pie weights (or dry beans like I use!). Bake in the preheated oven for 25 minutes or until the edges begin to turn lightly golden. Start preparing the fillings when the crust is baking (instructions below). Remove from the oven and very carefully lift the parchment paper and pie weights out of the pan. Use a fork to poke a few holes in the bottom of the pie crust and then let it cool slightly on a wire rack while you finish making the fillings.

Whisk together the melted butter, white sugar, egg, and vanilla in a mixing bowl. Add the cocoa powder and flour and whisk just until smooth and combined. Set aside.

Whisk together the melted butter, brown sugar, eggs, and vanilla in a mixing bowl. Fold in the chopped pecans. Set aside.

Preheat the oven to 375℉. Pour the brownie filling into the slightly cooled pie crust and spread it into an even layer. Then, pour the pecan filling on top and gently spread it evenly on top of the brownie filling.

Bake the pie in the preheated oven for 30-35 minutes or until the crust is nicely golden brown, the center has puffed up, and the nuts on top are toasted in appearance and fragrance. Let the pie cool on a wire rack for at least 2 hours before serving if you would like to serve it at room temperature or refrigerate for at least 4 hours (after it cools to room temperature) if you would like to serve it cold. This pie is great served at room temperature or cold with vanilla ice cream or whipped cream. Enjoy!