In a large bowl, combine flour, cocoa, sugar, and salt. Stir to combine.

Add oil and stir until mixture resembles coarse meal. Add the cold butter and toss to coat. Using a pastry blender or fork, cut in butter until no large pieces remain.

Add the cold water one tablespoon at a time until the dough gathers into a ball.

Divide the dough in half, making two discs. Wrap the dough and chill for at least one hour.

In a medium bowl, combine the flour and vegetable shortening. Using a pastry blender or fork, cut shortening in until no large pieces remain.

In a small bowl, combine egg, vinegar, and cold water. Whisk to combine.

Make wells in the flour mixture, and pour the egg mixture into the wells. Stir until a soft dough is formed.

Form the dough into a disc, wrap, and chill for at least one hour.

On a lightly floured surface, roll one disc of the chocolate dough large enough to fit your pie plate. Line the pie plate with the dough, then place the lined pie plate in the refrigerator to chill while you prepare the filling.

Pit the cherries, slice in half, and place in a large bowl. Add the lemon juice, vanilla bean paste, and chocolate extract. Stir to incorporate.

In a small bowl, combine the sugar, tapioca starch, and salt. Whisk to combine. Pour the sugar mixture in with the cherries and gently toss to coat. Gently stir in the chopped chocolate.

Pour the cherry filling into the lined pie plate, and return it to the refrigerator while you make the top crust.

On a lightly floured surface, roll the second half of the chocolate dough to about ¼" thickness. Repeat the process with the plain dough. Create a lattice (or other design) for the top of your pie using the two doughs.

Return the pie to the refrigerator to chill while the oven preheats.

Preheat oven to 400° F. Prepare the egg wash by combining the egg and water in a small bowl and whisking to combine. Brush the egg wash over the top of the pie. Sprinkle with raw sugar, if desired.

Place the pie on a baking sheet and bake for about 1 hour & 15 minutes. Check the pie after 30 minutes. If the top of the pie is getting too brown, you can tent it with foil during baking.

The pie must cool completely before slicing (or the pie will be a watery mess).