While the dough is chilling, make the ganache. Chop the chocolate into small
pieces and set aside. Put the cream into a milk pan or small/medium-sized
saucepan. Gently heat over a medium heat, stirring occasionally. When it’s
just coming to the boil, remove from the heat and transfer the chopped
chocolate into the pan. Let the mixture sit for a few minutes to melt, then stir
in the coffee extract and combine and until smooth and shiny. Leave to cool.
You want the ganache to have a soft spreading consistency when you come
to use it, so, once cooled, you may want to put it in the fridge to firm up a
little.