Add 1 1/4 cups of all purpose flour, 3 tablespoons of special dark cocoa powder, 2 tablespoons of unsweetened cocoa powder and 1/3 cup of granulated sugar into the food processor and pulse 2-3 times to combine
Add 2 teaspoons on vanilla extract and 1 large egg and pulse until you develop a coarse sand texture (12-15 pulses)
Add 13 tablespoons of cold butter cubes and pulse until a large crumble forms (see photos above)
Transfer the crumble onto a lightly floured work surface
Press the crumble into a ball and then gently smash the ball into a thick diskÂ
Wrap the disk tightly in plastic wrap and chill the dough in the refrigerator for 90 minutes
Unwrap the chilled dough and place it onto a lightly floured surface
Flour a rolling pin and begin working the dough out into a 12-13 inch round (if the dough is really hard, allow it to soften for just a few minutes and then continue rolling)
Loosely wrap the rolled out dough over a floured rolling pin and transfer it onto an 11 inch tart pan
Press the dough out flat and even and up the side walls
Use a sharp knife to remove any excess dough sticking above the sides of the tart pan
Cover the pan with plastic wrap and freeze the tart dough for 10-15 minutes
Remove the plastic wrap and cover the tart dough with foil, being sure to cover the edges and press the foil down gently against the doughÂ
Fill the middle of the tart pan with pie weights or dry rice
Bake the tart shell in a 375 degree oven for 20 minutes
Transfer the tart shell to a cutting board and carefully remove the weights and foil
*If you are using the tart shell immediately, return the tart shell to the oven and bake for 5 more minutes before adding your filling
*If you want to fully cook the tart shell to use later or with a no bake filling, return the tart shell to the oven for 10-12 minutes or until the shell feels set and no longer moist to the touch