The recipe is here, but I modify it to the best or closest to the best
http://www.bbc.co.uk/food/recipes/easy_chocolate_cake_31070
,Original recipe calls for 350 grams sugar, I lower it to 250 grams sugar and change it to muscovado sugar, 2 tablespoons coffee is my second alteration, Also the chocolate for the icing I increase it to 50% more chocolate so the icing will be firmer and not easy to melt. I tried 1:1 for icing and decide it is better to get have 50% more chocolate in it. I also modified this recipe to single layer cake, no icing in the middle, the main key to make it nice to eat is sugar and also the coffee, too little coffee and you can't taste the difference, 2 tablespoon is about right, many people use 2 teaspoon for this recipe, I use 2 tablespoon. the ingredients you see here is for 1 portion, Double portion is about right, double everything here except the icing, the icing should be enough even if the cake is twice as big as it has no layer in the middle.
Tips for making a better chocolate cake
1. Always use muscovado sugar, it gives it such a special caramel taste and is healthier and lower glycemic index too.
2. Always add coffee powder, preferably fresh coffee powder, but instant coffee powder will do
3. Use wholemilk and never low fat milk when you make cake, wholemilk is healthier than low fatmilk and taste better than lowfat milk, there are a lot of articles on the internet to find why wholemilk is healthier and less fattening than low fat milk on the internet.
4. Use the freshiest egg possibly, omega eggs is even better.
5. Use dark chocolate for icing or perhaps use hershey or van houten baking chocolate.
Also this recipe makes too little egg, best is double everything in this recipe, icing does not need to double if you do single layer icing. I prefer single layer icing, easier to make and cheaper, I calculated the cost, the most expensive part to make a chocolate cake is from the icing and not the cake, from the country i am from, ingredients for the icing is the most expensive.
Once you done all this, I can almost assure you the cake will be one of the best ever if not the best.
Here is my modification for the ingredients
For the chocolate icing
I only changed the ingredients of the cake, instruction how to make it is at the website.
What is muscovado sugar
http://en.wikipedia.org/wiki/Muscovado
It is unrefined sugar, not brown sugar mind you, but I guess brown sugar would be closer than white sugar but that is still not Muscovado, most brown sugar is white sugar added back the mollases, muscovado use some process where the moisture is evaporated and leaves what is behind and a good brand is billington muscovado sugar, they have the brown one and dark brown one, I can't tell exactly which is better because at one time I was using unbleached flour and another time I was using bleached flour and different recipe, but for unbleached flour I recommend gold medal as some other brands, if you use their bleached flour, the chocolate you put inside and other ingredients would coagulate and be concentrated in certain parts of the cake.