Place the flour, cocoa, sugar, and salt in a large mixing bowl and whisk to combine.
Stir in the olive oil, until the mixture resembles coarse meal.
Add the butter slices, tossing to coat.
Stir in the water, a tablespoon at a time, just until the dough gathers itself into a ball.
On a lightly floured surface, pat or roll the dough into a rectangle about 1/2-inch thick.
Fold it into thirds, like a letter.
Roll out again to a thickness of 1/2-inch.
Turn the dough 90 degrees and repeat two more times.
Wrap the dough in plastic wrap and refrigerate for 2 hours minimum.