Preheat oven to 320F (160C). Butter the sides and bottom of aprox. 8 x 4 inches ( 1 liter capacity) loaf pan and line with parchment paper.
Melt the chocolate and butter in a medium bowl, over bain-marie, stirring occasionally, until smooth. Remove the pan from heat but keep the bowl over the water. Stir in the sugar and then remove the bowl from the pan.
Incorporate cream and mix to combine and add salt.
Then add eggs one at a time into the mixture and whisk until well combined.
Pour the mixture into prepared pan and place the pan into a larger pan.
Pour hot water until about halfway up the sides of the pan.
Bake the terrine for 30 minutes.
Carefully remove the pan from the water bath and let cool to room temperature.
Cover and refrigerate for at least 3 hours before serving.
When serving it is best to let it sit to room temperature for about 20 minutes and cut into slices using a hot knife.