Chocolate Truffle Pie

A very rich, yummy chocolate pie, often requested from my Sunday School class for birthdays.  I had to make it for one of my class member's birthdays tomorrow, and thought I had lost the recipe, so when I finally found it decided it was about time to add it to the blog even for MY own sake in keeping track of it!

Warning: This pie is very rich, so don't serve out too large of pieces unless you know you can handle it! :)

Crust:

1 ¼ cups chocolate cookie crumbs (I crush enough oreos to make about 1 ½ cup)
¼ cup butter or margarine, melted

Filling:
1 bag (12 oz) semi-sweet chocolate chips (2 cups)
½ pint (1 cup) whipping cream
1 tsp. vanilla
2 egg yolks

Topping:
½ cup whipping cream
1 tbsp. powdered sugar
Unsweetened baking cocoa, if desired

In a small bowl, mix cookie crumbs and butter. In ungreased 9-inch glass pie plate, press crumb mixture in bottom and 1 inch up the side.

In a double boiler set over hot simmering water, heat chocolate chips 2 to 3 minutes, stirring frequently, until melted and smooth. Do not allow any water (even drops) to get in the chocolate, as it will make it grainy. Gradually add 1 cup whipping cream, stirring constantly, until combined. Stir in vanilla and egg yolks until well blended. Cook over medium-low heat 5 to 6 minutes, stirring frequently, until thickened and hot. Pour filling into crust. Refrigerate at least 3 hours until firm.
If want whipped topping, beat ½ cup whipping cream and the powdered sugar with an electric mixer on high speed 1 to 2 minutes or until soft peaks form. Top individual servings with whipped cream, and dust with cocoa if desired.