This old bake-off recipe from the “Ice Box Pie” category is a Southern favorite. It’s basically a chocolate mousse in a crust, and it’s an absolute bitch to make, but so damn worth it.
Use an oiled glass pie pan. Drape crust over a rolling pin and ease it into the pan without stretching. Gradually work the crust firmly against the sides and bottom. Moisten your fingers and fill in the cracks. It helps to pop it into the freezer for five minutes or so to keep it from slumping down the sides. Generously prick the crust on the bottom and sides to prevent bubbling, and line the inner edges with heavy-duty aluminum foil. Bake the crust for 10 minutes at 300 with the foil, remove the foil and return to the oven to brown.
Whip a cup of heavy cream to stiff peaks, cover, and chill. Melt 8 oz. chopped bittersweet chocolate (I use a glass bowl in the microwave). Stir until smooth and set aside. Add 3 eggs, ¾ cup sugar, and a couple of tablespoons of water to glass bowl. Beat with an electric mixer 5 minutes, until pale yellow and thick. Place this bowl over a smaller pot of simmering water and cook, whisking continually, until the mixture is hot through and through. Remove from heat and continue beating until cooled and fluffy. (This might take up to 10 minutes because you want some serious fluff.) Add the melted chocolate, 2 teaspoons vanilla, a stick of very soft butter, and beat until very smooth. Now carefully blend in the whipped cream, just until you have a more or less even color; don’t over-mix.
Pour mixture into crust and spread evenly. Top with another half cup of whipped cream sweetened with a quarter cup powdered sugar and a teaspoon vanilla (or almond) extract. Spread over chocolate filling. Cover lightly with plastic wrap and refrigerate for at least three hours.