Chocolate Cream Pie

ingredients
1 9″ pie crust, baked
4 egg yolks, beaten
1 1/2 C sugar
4 T cornstarch
1/2 C unsweetened cocoa powder
1/2 t salt
3 C milk
1 T butter
1 1/2 t vanilla extract
1  frozen whipped topping, thawed

directions
In a large mixing bowl, cream together egg yolks and sugar.  Mix in cornstarch, cocoa power and salt.  Add milk and stir gently.

Pour mixture into a large saucepan and cook over medium heat, stirring constantly, until boiling.  Remove from heat.  Stir in butter and vanilla extract  Cool slightly, then pour mixture into pie crust.  Chill before serving and garnish with whipped topping.