Make the crust: Whisk together flour and salt. Cut in cold butter until the mixture resembles coarse crumbs. Gradually add ice water, mixing until the dough comes together. Chill for at least 30 minutes.

Roll out the dough into a 12-inch circle. Transfer to a 9-inch pie plate. Trim and crimp the edges. Prick the bottom with a fork.

Line the crust with parchment paper and fill with pie weights or dried beans. Bake at 375°F (190°C) for 15 minutes.

Remove weights and parchment paper; bake for another 5-7 minutes, or until lightly golden. Set aside to cool completely.

Make the filling: In a large bowl, whisk together sugar, cocoa powder, flour, and salt. Add eggs one at a time, whisking well.

Stir in milk and vanilla extract. Gradually whisk in melted butter.

Pour filling into the cooled crust. Bake at 350°F (175°C) for 40-45 minutes, or until the filling is set (center may be slightly jiggly).

Let cool completely on a wire rack before serving. Refrigerate for at least 2 hours for best results.