In a large bowl, mix together 200 g cookie crumb and melted 6 tablespoons butter. The mixture should be moist and hold together well.
Transfer the mixture to a 9-inch pie dish and gently pat down with your fingers so that some of the mixture goes up the sides of the dish.
To make the filling
In a medium saucepan add 50 g cocoa powder, 700 ml warm milk, 250 g sugar, ¼ teaspoon salt, and 50 cup g cornstarch and stir to mix.
Place on medium heat, and stir once in a while to ensure it does not stick to the bottom.
Allow to boil for one minute, then remove from heat.
Add 3 tablespoons butter and 1 ½ teaspoons vanilla extract, stirring well into the mixture till it becomes glossy.
Pour over the cookie base. Allow the pie to cool on the counter, then lay a sheet of cling film over the top of the chocolate pie, pressing out any air bubbles, to achieve a smooth finish.
Refrigerate until set (1-2 hours) and serve with a scoop of ice cream.
For the base, instead of making a cookie crumb, you could use a store bought pie crust.Use a good quality cocoa powder - it makes such a difference.Keep in a sealed container in the fridge for up to 4 days.