Step 1

Bake pie shell; cool. Stir together sugar, cornstarch and salt in a 2 quart saucepan. Combine egg yolks and milk in a container with a pouring spout. Gradually blend milk mixture into sugar mixture.

Step 2

Cook over medium heat, stirring constantly, until mixture comes to a boil. Boil and stir for 1 minute. Remove from heat; stir in butter and vanilla. Add 1-3/4 cups of chocolate chips; stir until the chips are melted and mixture is well blended. Pour into prepared pie shell; press plastic wrap onto filling. Cool. Refrigerate for several hours or until chilled and firm. Garnish with whipped cream and leftover chocolate chips, if desired.