On a roll now with our new eclairs. The newest member of the family being what I believe to be one of my favorite things to eat: a coffee eclair. We simply combine pastry cream with soluble coffee crystals (VIA, of course, not Sanka or Nescafe... not that there's anything wrong with those brands...) which flavor the cream very intensely. The glaze also also contains coffee but in liquid form (thank you Trablit).
Enjoy. I certainly did... about two or three.