Crust:
2 1/2 cups all-purpose flour
1 teaspoon fine salt
2 tablespoons granulated sugar
3/4 cup unsalted butter, cubed
1/2 cup shortening
8 tablespoons ice water

Filling:
1 3/4 cup + 2 tablespoons granulated sugar
4 tablespoons + 1 teaspoon unsweetened cocoa powder
1/4 teaspoon fine salt
6 tablespoons butter, melted
8 ounces evaporated milk
1 tablespoon vanilla extract
3 eggs

2 1/2 cups all-purpose flour 1 teaspoon fine salt 2 tablespoons granulated sugar 3/4 cup unsalted butter, cubed 1/2 cup shortening 8 tablespoons ice water 1 3/4 cup + 2 tablespoons granulated sugar 4 tablespoons + 1 teaspoon unsweetened cocoa powder 1/4 teaspoon fine salt 6 tablespoons butter, melted 8 ounces evaporated milk 1 tablespoon vanilla extract 3 eggs

Combine flour, sugar, and salt in food processor and pulse to mix. Add about half of the butter to the food processor and pulse several times. Add the rest of the butter and pulse 8 more times until the largest pieces of the butter are about the size of large peas. Sprinkle the mixture with about half of the water, and pulse again. Then add the rest of the water, a tablespoon at a time, pulsing twice after each addition, until the dough just barely begins to hold together. You know that the mixture is ready if, when you pinch some of the crumbly dough together with your fingers, it holds together. Be cautious with the amount of water you add. Too much, and the crust will be tough. Carefully empty the crumbly dough mixture from the food processor onto a clean, dry, flat surface. Gather the mixture in a mound. At this point, you can push down with the palm of your hand on the dough crumbles a few times. This will help flatten the pieces of butter into layers, which will help your crust be flaky. Divide the dough mixture into two even-sized mounds. Use your hands to form each one into a disk. Do not over-knead! Kneading develops gluten, which will toughen the dough. If you started with cold butter, you should be able to see small chunks of butter speckling the dough. This is a good thing. These small bits of butter with spread out into layers as the crust cooks, so you have a flaky crust. Sprinkle each disk with a little flour, wrap each one in plastic wrap, and refrigerate for 1 hour, or up to 2 days.

After proper chilling time, remove one crust disk from the refrigerator. Let sit at room temperature for 5-10 minutes in order to soften just enough to make rolling out a bit easier. Roll out with a rolling pin on a lightly floured surface to a 12-inch circle, about 1/8 of an inch thick. As you roll out the dough, check if the dough is sticking to the surface below. If necessary, add a few sprinkles of flour under the dough to keep the dough from sticking. Carefully place onto a 9-inch pie plate. Gently press the pie dough down so that it lines the bottom and sides of the pie plate. Use a pair of kitchen scissors to trim the dough to within 1/2 inch of the edge of the pie dish. Freeze the crust for at least 30 minutes, until chilled. This is an important step in pre-baking. Otherwise the crust will slip down the sides.

Preheat oven to 350 degrees. When the crust is sufficiently chilled, line the pie crust with parchment paper, wax paper, or aluminum foil. Fill at least 2/3 full with pie weights; dry beans, rice, or stainless steel pie weights. Bake with weights for 20 minutes. Remove from oven, cool a few minutes, and carefully remove pie weights. Poke small holes in the bottom of the pie crust with a fork or knife, and return to oven, without the weights, and cook for an additional 10 minutes, until the crust is golden. Cool completely before filling.

Mix sugar, cocoa, and salt together. Beat the eggs, then add to the cocoa mixture. With an electric mixer, beat in the milk, butter, and vanilla. Pour mixture into pie shell, covering the edges with aluminum foil to avoid burning the edges, and bake for 45 minutes, or until set. Top with sifted powdered sugar, if desired. Let cool before slicing.