Whisk the Dry Ingredients: In a large mixing bowl, whisk together the flour, cocoa powder, sugar, and salt until the color is uniform and no lumps of cocoa remain.
Incorporate the Oil: Stir in the 2 tablespoons of oil. Use a fork or pastry blender until the mixture looks like coarse meal or wet sand.
Add the Butter: Toss in the cold butter slices, coating them in the flour mixture. Do not over-mix; you want the butter to remain in distinct, cold pieces.
Form the Dough: Add ice water one tablespoon at a time. Stir gently until the dough just begins to clump together and can be gathered into a ball. Wrap in plastic and chill for 1 hour.
The Lamination (Folding): On a lightly floured surface, roll the dough into a rectangle about 1/2-inch thick. Fold it into thirds (top down, bottom up) like a letter. Roll out again to 1/2-inch thick, turn 90 degrees, and repeat this process two more times.
Final Chill: Wrap the folded dough tightly in plastic wrap and refrigerate for a minimum of 2 hours (or overnight) to allow the layers to set.
Roll and Fit: Dust your work surface with flour. Roll the dough out until it is 1–2 inches larger than your pie plate. Carefully roll the dough around your rolling pin to transfer it to the dish.
Trim and Crimp: Trim any overhanging edges, then roll the excess under itself and crimp the edges with your fingers or a fork for a decorative finish.