Break the butter biscuits with your hands into smallish pieces. Place into a bowl.
Cook: Place the milk and sugar into a small pot and bring to a boil while stirring from time to time. Boil for about 1 minute. Add the butter and stir until melted.
Combine: Take off the heat, add the cocoa and the rum aroma and stir well. Pour this mixture over the biscuit pieces and mix well until all the biscuit pieces are coated with the cocoa mixture.
Shape salami: Cut two pieces of plastic wrap/cling film. Divide the mixture in two and place each batch on one of the cling film pieces. Form a rough sausage (as thick as you like it) and wrap it carefully into the cling film to form a “salami.” Repeat with the second batch.
Refrigerate until they are firm, for several hours or overnight. Slice before serving.
You can use real rum if not serving this dessert to children. Or you could leave this out altogether, it is optional, but most people like it.