Chocolate sheet cake (Debbies birthday cake)

So I must confess that while I love pies I have a fear of cake baking.
I know it isn't rational but there is a lot that can go wrong in a cake and you would never know until it comes out of the oven.
For example this chocolate sheet cake which I baked twice because the first time I mixed up the measuring cups and thought I was using a one cup when I was really using a 1/3 cup. I realized when I poured it in the pan that something was probably wrong but it wasn't until it came out of the oven too small, too thin and too eggy that we figure out what happened.

So I showed up to spend the weekend at the Longman's for Aunte Debbies birthday and found that I had forgotten something ... a present for her b-day.(Oops)
So instead of worrying about it I baked the cake of her choice a chocolate sheet cake with chocolate icing.
Yum

The recipe goes like this
Take one cup water, two sticks of margarine and four table spoons of coco and put them in a sauce pan.
bring to a boil. In a seperate bowl add two cups of flour and two cups of sugar.
Once the stuff in the pan boils add a teaspoon of vanilla, a teaspoon of baking soda, two eggs(lightly beaten) and a half a cup of buttermilk.  Stir it all up and them pour it over the flour/sugar mix. Stir for two minutes.
Put the whole thing in a baking pan
Bake at 325 for 30ish minutes.
(credit to Sandy Wallace)

ICING
So the icing is a little tricky but fun
Take a sauce pan and put a stick of margarine in it.
Add 6-7 table spoons of milk and four tablespoons of coco powder.
bring to a boil (slowly!)
Once it is boiling stir in a pound of icing (powdered) sugar.
 turn off the heat.
It might be watery but don't worry it will stiffen up.
(credit to Sandy Wallace)