For the beginner's pie crust: Combine the flour and salt in the bowl of a food processor fitted with the blade attachment. Add the butter and vegetable shortening and process until the mixture resembles coarse meal, 8 to 10 seconds. With the processor on pulse, add enough of the ice water, 1 tablespoon at a time, until the dough holds together without being sticky or crumbly. Shape the dough into a disk and wrap in plastic wrap. Chill until firm and the moisture has distributed evenly, about 30 minutes.
Flour a clean work surface and a rolling pin. Place the dough disk in the center of the floured surface. Starting in the center of the dough, roll to, but not over, the upper edge of the dough. Return to the center, and roll down to, but not over, the lower edge. Lift the dough, give it a quarter turn and lay it on the work surface. Continue rolling, repeating the quarter turns, until you have a disk about 1/8 inch thick.
Ease the pastry into a 9-inch pie plate. Trim 1 inch larger than the diameter of the pie plate; fold the overhanging pastry under itself along the rim of the plate. For a simple decorative edge, press the tines of a fork around the folded pastry. To make a fluted edge, using both your finger and thumb, pinch and crimp the folded dough. Chill until firm, about 30 minutes.
To blind-bake the crust, preheat the oven to 425 degrees F.
Crumple a piece of parchment paper, and then lay it out flat over the bottom of the pastry. Weight the paper with pie weights, dried beans or uncooked rice; this will keep the unfilled pie crust from puffing up in the oven. Bake for 20 minutes. Remove from the oven and remove the paper and weights. (You can reuse the rice or beans for blind-baking a number of times.) Return to the oven and bake the empty shell until a deep golden brown, about 10 more minutes (for 30 minutes total).
For the filling and meringue: While the pie crust is warm, brush the bottom with the melted chocolate and set aside.
In a saucepan, combine 1 cup of the milk and the granulated sugar. In a bowl, combine the remaining 1 cup of milk, the cocoa powder and flour and whisk thoroughly to combine. Heat the saucepan with the milk-sugar mixture over medium-high heat until simmering. Slowly add the milk-flour mixture and stir to combine. Bring to a boil. Add the egg yolks, whisking constantly, and heat until it returns to a boil. Once the mixture comes to a boil, immediately add the vanilla and remove it from the heat. Pour the mixture into the baked pie crust. Set aside to cool completely and set, about 2 hours at room temperature or 1 hour refrigerated.
Preheat the oven to 500 degrees F.
To make the meringue topping, place the egg whites in a nonreactive bowl with a pinch of salt. Add the cream of tartar and, using a hand-held mixer, whisk on high speed until foamy. Sift over the confectioners' sugar a little at a time and whisk until the whites are glossy and hold stiff peaks when the whisk is lifted.
To finish the pie, spoon the meringue over the pie, making sure it touches the edges of the pie crust. Bake until golden brown, 3 to 5 minutes. Using a serrated knife, cut the pie into wedges and serve.
It may seem quite odd to add the egg yolks to the simmering custard without tempering them or winding up with scrambled chocolate eggs. The reason it works is science--the starch in the flour prevents the eggs from curdling at their normal temperature, allowing you to bring the custard to a boil.
Recipe courtesy of Virginia Willis