Soak the sultanas in 2 tablespoons of cognac for 10 minutes.
In a large bowl, break the biscuits with your hands into medium size pieces. Add the almonds, butter, cocoa powder, the rest of the cognac and the condensed milk. Add the soaked sultanas and stir it all very well. This will be a very stiff dough and the best way to mix it all is by using your hands. It may seem like it’s not going to come together, but it will, just keep mixing it up until all ingredients are well incorporated, forming a dark, moist dough.
Place a double layer of cling film onto a clean work surface and put 1/3 of the dough in the middle. Using your hands, shape dough into a log about 5 to 7cm in diameter. Place log towards one end of the cling film and start rolling the film tightly around the log. Twist the ends of the plastic and tuck them under the log.
Repeat this process to make three logs. Refrigerate the logs overnight.
When ready to serve, use a small sieve to sprinkle the outside of the logs with icing sugar (or, if you prefer, sprinkle the icing sugar on a piece of kitchen paper and roll the log on it). Slice it with a sharp knife. Enjoy it!
This freezes well. In theory you could make one big log..but it is much easier to handle the dough in smaller amounts and it means you can have a chocolate salami in th freezer to take to parties or for guests, etc.