1. First pipe choux fingers on parchment paper lined baking sheets. If you use pastry tip, choose half inch round pastry tip.
2. In the egg yolk, add in the water and mix. And brush the choux with egg wash. This will make the top shiny and brown. Then on top of choux score with a fork dipped in egg wash.
3. Bake at 390 degrees F (200 C) for 15 minutes. Then reduce to 360 degrees F (180 C) and bake for another 12-14 minutes, or until puffed and golden brown. Then let cool on a wire rack.
Make chocolate ganache
4. To make chocolate ganache, melt the chocolate on a double-boiler. If you want faster alternative, zap the chocolate in the microwave. Meanwhile add the cream in a mini sauce pan and bring to a boil. Pour the cream into the melted chocolate and stir until combined.
6. On the bottom of the éclairs, make two holes with a tip of a small knife. With a small plain pastry tip, pipe filling into one of the holes. Stop piping when pastry cream starts to come out of the other hole. You can make holes on top if you want.
7. Glaze Dip éclairs into the ganache and remove excess chocolate wiping with an index finger.
8. When cooled, ganache has really spreadable consistency. To decorate on top, you can use melted white chocolate. And I am using violet food color.