This is a recipe from an old Country Woman Magazine.
1 9-inch baked pie shell
1 1/4 cups granulated sugar
1/4 cup cornstarch
1/4 tsp salt
3 cups milk
3-oz unsweetened chocolate, chopped
4 egg yolks, lightly beaten
3 tbsp butter
1 1/2 tsp vanilla extract
In large saucepan, combine sugar, cornstarch and salt; stir in the milk and chocolate. Cook, stirring, over medium-high heat until thick and bubbly. Reduce heat and cook while stirring for another 2 minutes. Remove from heat.
Stir a small amount of the filling mixture into the egg yolks then return mixture to the pan while stirring constantly. Bring mixture to a gentle boil; cook, stirring for 2 more minutes. Remove from heat.
Gently stir the butter and vanilla extract into the filling. Transfer filling into the baked pie shell and cool on a wire rack.
Chill pie for three hours before cutting to serve.
To serve, dollop with whipped cream, if desired.
Option: Dark Chocolate Meringue Pie - After tranferring the filling into the shell, cover with your favorite meringue and bake until meringue is lightly browned.