With an electric mixer or wooden spoon, beat the butter or margarine until soft. Beat in the caster sugar.
Add the flour and coffee and mix by hand to form an evenly blended dough. Wrap in a plastic bag and refrigerate at least 1 hour.
Lightly sprinkle the work surface with icing sugar. Knead the dough on the sugared surface for a few minutes to soften it slightly.
Using a rolling pin dusted with icing sugar, roll out the dough to ⅛ in (3mm) thickness. With a 2½ in (6cm) fluted pastry cutter,cut out 16 rounds. Transfer the rounds to the prepared baking trays. Refrigerate for at least 30 minutes.
Preheat a 150°C oven. Bake the biscuits until they are lightly golden, about 30 minutes. Let them cool and firm up before removing them from the trays to a wire rack to cool completely.
Remove the ice cream from the freezer and let soften 10 minutes at room temperature.
With a metal spatula, spread the ice cream evenly on the flat side of eight of the biscuits, leaving the edges clear. Top with the remaining biscuits, flat-side down.
Arrange the ice cream sandwiches on a baking tray. Cover and freeze at least 1 hour, longer if a firmer sandwich is desired.
