Add cocoa powder and mix to combine. Whisk continuously to break the lumps.
Add Turkish delight and mix until the Turkish delight is half melted. Add rum extract.
Add raisins and walnuts and mix to combine.
Into a large bowl, break social tea biscuits into 1/2" to 1" pieces.
Pour the chocolate mixture over biscuits and mix until the biscuits are evenly covered.
Spread plastic wrap on the table and with the help of a spoon or spatula, add half the mixture in the middle of the wrap. Shape into a log and fold the bottom half of the wrap over the top half.
Grab the ends of the plastic wrap and twist to seal.
Roll the log on the table while lightly pressing and pushing the salami mixture, until the plastic wrap is tight and the mixture is compact.
Refrigerate for a few hours (or overnight) until the log is hard.