Spoon the pastry dough into a piping bag with a plain tube nozzle.
Pipe, in 5 cm./ 2 in.
lengths, on to well-greased baking sheets.
Put into the oven preheated to fairly hot (200°C/400°F or Gas Mark 6) and bake for 10 minutes.
Reduce the oven temperature to moderate (180°C/350°F or Gas Mark 4) and continue to bake for 20 to 25 minutes, or until the eclairs are puffed up and golden brown.
Make a slit in the side of each eclair and, using a teaspoon, carefully scoop out any soft dough from inside.
Return to the oven for 5 minutes to dry out.
Cool on a wire rack.
To make the filling, beat all the ingredients together until the mixture is very thick.
Slice the eclairs in half, lengthways, and fill generously with the filling.
To make the icing, mix together the icing sugar and coffee.
Dip the tops of the eclairs in the icing, or spread it with a knife.