Preheat the oven to 350°F (175°C).

If using a homemade crust, roll it out and place it into the 9-inch pie pan. Trim and crimp the edges if desired.

Pre-bake the crust if you prefer a sturdier base. Blind-bake by adding pie weights over parchment paper for about 10 minutes. Allow it to cool.

In a mixing bowl, whisk together the sugar, cocoa powder, flour, and salt until thoroughly combined. This ensures an even texture in the filling without lumps of cocoa or flour.

In a separate bowl, beat the eggs lightly, then add the melted butter, evaporated milk, and vanilla extract. Whisk until smooth and creamy.

Pour the wet ingredients into the dry ingredients and stir until everything is well combined. The mixture should be smooth and thick with no visible lumps.

Pour the filling into the prepared pie crust. Use a spatula to spread it evenly.

Bake the pie in the preheated oven for 35-40 minutes, or until the top is set and has a slightly crackly texture. The filling will continue to firm as it cools.

Remove the pie from the oven and allow it to cool on a wire rack for at least an hour before slicing. This cooling step helps set the filling.