Prepare an ice-water bath. In a heatproof bowl set over simmering water, melt chocolate. Set aside. Sprinkle gelatin over water in a small bowl and set aside to soften.
Whisk together in a medium bowl 4 egg yolks, 1/4 cup sugar, and the cornstarch. Set aside. In a medium saucepan, combine milk and 1/4 cup sugar. Bring just to a boil. Add about 1/4 of the milk mixture to the egg mixture, whisking constantly, until combined. Return to saucepan and bring to a boil. Remove from heat when mixture has boiled and thickened, 3 to 4 minutes.
Measure 1 cup of custard and add the melted chocolate and vanilla to it. Cool completely over ice-water bath. When cool, spread evenly in the bottom of the pie crust. Transfer pie crust to refrigerator until set, about 5 minutes. Add gelatin to remaining custard. Cool over the ice-water bath until just beginning to set.
In the bowl of an electric mixer fitted with the whisk attachment, beat egg whites with salt and cream of tartar until soft peaks form. With machine running, gradually add remaining 1/2 cup sugar and beat until stiff glossy peaks form. Stir 1/3 meringue into custard to lighten. Gently, but thoroughly, fold in remaining meringue and rum. Spread over chocolate layer. Refrigerate pie for at least 3 hours and up to overnight.
Whip cream until stiff. Spread over custard or pipe on top with a pastry bag fitted with a star tip. Sprinkle chocolate shavings on top. Chill until ready to serve.
2 1/2 cups all-purpose flour
1 teaspoon salt
1 teaspoon sugar, optional
1 cup (2 sticks) cold unsalted butter, cut into small pieces
To the bowl of a food processor, add flour, salt, and sugar; all ingredients should be cold. Add the pieces of butter and process for approximately 10 seconds, or just until the mixture resembles a coarse meal. (To mix by hand, combine the dry ingredients in a large mixing bowl. Using a pastry blender or 2 table knives, cut in the butter until the mixture resembles coarse meal.)
Add 1/4 to 1/2 cup ice water, drop by drop, through the feed tube with the machine running, just until the dough holds together without being wet or sticky; do not process more than 30 seconds. Test the dough at this point by squeezing a small amount together. If it is crumbly, add a bit more water.
Turn the dough out onto a large piece of plastic wrap. Grasping the ends of the plastic wrap with your hands, press the dough into a flat circle with your fists. This makes rolling easier than if the pastry is chilled as a ball. Wrap the dough in the plastic and chill for at least 1 hour.
Lightly butter or spray with vegetable cooking spray the pie plate(s) or tart pan(s) you will be using. On a lightly floured board, roll out the pastry to a thickness of 1/8-inch. Place the pastry in the tart pan, pie plate, or pastry ring, which has been set on a parchment-lined baking sheet, and press it into the bottom edges and along the sides. Trim the pastry using scissors or a sharp paring knife, or by rolling a rolling pin across the top of the pan.
Crimp or decorate the edges of the pastry, if desired. Chill the pastry-lined pan until ready to use. Unbaked pastry shells can be refrigerated, well wrapped in plastic, for up to 1 day; for longer storage, they can be frozen.
Yield: 2 (8 to 10-inch) tarts or single-crust piecrusts, or 1 (8 to 10-inch) double-crust piecrust
Prep Time: 30 minutes
Cook Time: none
Inactive Prep Time: 1 hour
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