Beat egg yolks with half of the sugar and the melted margarine. (melt margarine in the micro for about 20 seconds - you don't want it to be too hot or it will cook the egg yolks when you add it).
Mix the other half of sugar with the cocoa and flour and add the 1/4 cup of scorching hot water. Mix with a whisk until smooth.
Combine the two mixtures and mix thoroughly.
Add vanilla and milk and mix thoroughly.
Don't get upset if mixture seems thin. It will set after baking.
Pour into an unbaked pie shell and cover the edges with foil or a pie ring to prevent the crust edges from browning excessively. Bake for 55-60 minutes at 325. It will still be a little jiggly bit it will set up nicely as it cools.
Let cool at room temperature for a couple of hours and then put it in the fridge for a couple of hours to cool good and proper.
Then - serve well chilled with homemade whipped cream or just be white trash like me and use Cool Whip.
Note: Most chocolate cakes and pies etc. have a small amount of salt because salt greatly enhances the flavor. Even candy bars have quite a bit of salt in them. This recipe calls for no salt because margarine has a lot of salt. If you substitute unsalted butter for the margarine add a 1/2 tsp to the recipe.