CHOCOLATE PIE

1    9" baked pie shell
3/4 cup sugar
1/8 tsp salt
1/4 cup cocoa
1/4 cup flour
2 cups milk
1 egg,slightly beaten
2 tsp margarine
1 tsp vanilla
Dream whip topping
Mix sugar,salt,cocoa,and flour,add egg and milk.Cook in microwave app.5 mins on 100% power, stirring occasionally during the cooking ,until it has thickened.Add butter and vanilla.
Pour in baked pie crust and top with whipped topping.