Granny's Chocolate Pie

Why I Love This Recipe
I've always been told this recipe was handed down from my Grandmother who is now 96, but I don't really believe that is exactly true. I doubt my grandmother used premelted chocolate and hers always looks darker than mine. Sooo, I'm thinking somebody adapted it somewhere down the line.
Ingredients You'll Need
1 heaping cup sugar
2 tbsp corn starch
3 tbsp flour
3 cup milk
5 egg yolks
1 pkg premelted chocolate (Nestles ChocoBake \ Unsweetened
3 tbsp butter
1 tsp vanilla
1 baked pie shell (melt 1 stick butter, add 1 cup flour, 1 cup chopped pecans and 1 tbsp sugar. mix and press into pie pan. bake at 350 until golden)
Directions
In saucepan mix sugar, corn starch and flour.
Add 1 cup milk. Stir thoroughly.
Mix separately: 5 egg yolks and 1 cup milk.
Stir egg mixture into saucepan. Stir well - no lumps
Add 1 cup milk - whip with whisk.
Add premelted chocolate.
Stir well - alternate whisk with wooden spoon or wooden spatula
Cook on medium heat, stirring constantly until mixture starts to boil.
Remove from heat, let cook for 5 minutes, stir in butter and vanilla.
Pour into pie shell and cover immediately with plastic wrap.
(Plastic wrap prevents film from developing on top)
Once cooled, top with cool whip and sprinkle with a few chopped pecans and/or chocolate curls.