Chocolate Cream Pie

2 baked 9" pie shells
1 quart milk
2 cups half-and-half
2 Tb butter
3/4 cup sugar
3 egg yolks
1/2 cup sugar
1/4 tsp salt
1/2 cup cornstarch
2/3 cup plus a few semisweet chocolate chips
1 1/2 tsp vanilla
Whipped cream

Reserve up to 1 cup of milk to mix with cornstarch. Place remaining milk in top of a double boiler and add half-and-half, butter, and 3/4 cup sugar. Cook until butter is melted and milk looks scalded.
In a bowl, whisk egg yolks until well broken up; then add 1/2 cup sugar and salt and whisk together very well. Slowly add this mixture to the hot milk mixture, stirring constantly. Stir for approximately 1/2 minute and then allow to cook for 15 to 20 minutes. (This gives the eggs time to cook and start the thickening process. Undercooking at this point slows the finishing process down by as much as half an hour.)
Mix reserved milk and cornstartch together and slowly add to the hot mixture. Be careful to stir constantly or lumps will form. Continue to stir for at least 2 minutes and every 5 minutes for the next 15 to 20 minutes.
A good test to see if the pudding is done enough is to stand up the whisk in the middle of the pudding with the whisk touching the bottom of the pan. If the whisk will stay straight up after you let go, the pudding is thick enough.
When the pudding is thick enough, stir in chocolate chips. Stir well until chips are melted. Stir in vanilla. Remove the whole double boiler from stove (the hot water will help keep the pudding hot while you dish up the pies).
Pour filling into pie shells. Fill pies so the tops are a little rounded. When cool, top with whipped cream and garnish with chocolate chips, if desired. Makes 2 pies.