Add the butter pats, tossing to coat. Add the cold water a little at a time until the dough comes together.

Chill in the refrigerator for 1 hour.

On a lightly floured surface, pat or roll the dough into a rectangle about 1/2-inch thick. Fold it into thirds, the way you’d fold a letter. Roll out again to about 1/2-inch thick. Turn the dough and repeat two more times.

Wrap the dough and chill it for at least 2 hours.

Dust your counter with flour and roll the dough out a little bigger than your pie plate.

Loosely roll the dough around your rolling pin and unroll it over the dish. Trim the extra dough, then roll and crimp the edges however you like.

Bake in a preheated 375°F oven for 20 minutes. Set it aside and let it cool all the way.

In a large saucepan, whisk the sugar, cornstarch, and cocoa together.

Whisk in the milk and stir continuously over medium heat until the mixture thickens and is bubbling.

Let it cool on the counter for about an hour, then move it to the fridge to finish chilling.

In a large bowl, whip the cream until stiff peaks are just about to form.

Add the vanilla and confectioners sugar and keep mixing until you’ve got good peaks. Don’t go too far or the texture gets weird.

Once it looks thick and fluffy, go ahead and spread it over the chilled pie.