Preheat oven to 350 degrees F.
In a medium-sized bowl, fitted into a saucepan, covering but not touching barely simmering water, melt chocolate and butter.
Add the coffee and sugar and continue to whisk to dissolve the sugar. Continue cooking until very hot approximately 120 degrees F.
Remove from the heat and whisk in the eggs. Pour into foil-lined loaf pan and bake in a water bath for 40 minutes.
Let cool, then chill overnight. Turn out the next day and serve in slices.