1.Place the first three ingredients into a double boiler to melt the butter and chocolate together. Mix with whisk to ensure there are no lumps. Remove from heat and set aside.
2.Mix eggs and sugar with hand mixer or whisk until the eggs become a pale yellow and fluffy.
3.Add the chocolate to the eggs in a slow, steady stream until all is mixed in. Thoroughly mix together for just a couple more minutes.
4.Generously spray the loaf pan and pour the mixture into it.
5.Wrap the loaf pan 3 times with the plastic wrap. Start by pulling the wrap out and laying the pan on top of the wrap. Fold the loose end over the pan and tear enough off the roll to cover the top again. Repeat this 2 more times. (This creates a seal that won’t come undone during the steaming process)
6.Place in roasting pan and fill with enough hot water to come half way up the sides of the loaf pan. Cover the roasting pan with tin foil and place in pre-heated oven at 350 for two hours. Remove from oven when time is up and allow to cool (still wrapped) at room temp for two hours before cooling overnight. (The chocolate mix will still be quite loose when it comes out of the oven. This is normal. If the chocolate appears to be runny and not loose, place back in the oven for about 20-25 more minutes As it cools you will notice that it will start to set and then completely set the next day after cooling overnight.)
7.Separate the sides and ends of the pan and place upside down and peal the silicon off the chocolate. Turn right side up carefully with your hands. Slice with a warm knife for clean cuts (run under hot water and wipe dry just before slicing).