Pick your pan size and Spray the sides with Bakers Joy and line the bottom with parchment paper - I like to use a 10x3 inch round pan, You can use a 12x2 inch pan or two 8x2 inch pans
Heat 2 C of the sugar in a medium pan with the water until the sugar has completely dissolved to a syrup.
Place the butter in the hot syrup and stir, then add the chocolate and stir to combine until the chocolate melts and the mixture is smooth. Remove from heat and cool slightly.
Beat the eggs with 1 C sugar until the volume quadruples-this only takes 10 minutes in my Bosch - They really do quadruple in size.
Turn the mixer on slow and add the chocolate mixture to the eggs until just combined.
Pour into the cake tin of your choice and place in a water bath (I just use the next cake pan up). It is vital for even baking.
Bake in the oven for at least an hour. Depending on how thick your making your cake you MIGHT need up to an additional 30 minutes until it's set.
It's actually very hard to over cook. And the center tends to be goopy if it's undercooked, so always err on the side of cooking a bit too long.
The cake rises quite a bit when it cooks (expanding egg bubbles), but it does shrink as it cools so flip it over onto a plate or cake stand while its still warm, but leave the cake pan on to hold the shape, once it's cool you can take it off.