Combine the sugar, flour, salt, and cocoa powder in a small bowl.

Separate three eggs. Place the yolks in a medium saucepan and the whites in a mixing bowl for meringue.

Whisk the egg yolks in the saucepan, then add the heavy cream, milk, and water. Mix well.

Cook over medium heat, stirring constantly with a long-handled wooden spoon until it starts to boil.

When it reaches a low boil, add the dry ingredients and whisk to combine. Return to stirring with the spoon.

Add the butter and continue stirring until the mixture thickens to a pudding-like consistency.

Remove from heat and stir in 2-3 teaspoons of vanilla. Pour the filling into the baked pie crust.

If topping with meringue, do so now. Let the pie cool on a rack until the plate is no longer hot, then refrigerate for at least one hour before serving.

For whipped cream: Cover the pie with parchment paper or plastic wrap to prevent a skin from forming. Let it cool on a rack until the plate is no longer hot, then refrigerate for at least one hour before serving.

To Make Meringue:

Whip the egg whites on high speed until fluffy.

Reduce speed to low and gradually add 5 tablespoons of sugar, one tablespoon at a time, until fully incorporated.

Return to high speed and beat until stiff peaks form. Spread over the pie and brown under the broiler, watching carefully.

To Make Sweetened Whipped Cream:

Chill a bowl, then whip 1 cup heavy whipping cream at high speed until it begins to stiffen.

Gradually add 3 tablespoons of sugar, one tablespoon at a time. Continue beating until stiff peaks form.

Store in the refrigerator until ready to use. Add 1 teaspoon of vanilla flavoring after the sugar for vanilla whipped cream.