Put water, butter and salt to medium heat and bring to boil.
As soon as it starts boiling take it off the heat and add flour and mix vigorously until combined.
Cook for 1 more minute on medium heat, stirring continuously vigorously to cook all the flour. This consistency of the dough should be same as a soft play dough.
Allow to cool for approximately 5 minutes. It should be warm to touch but not hot.
Whisk the eggs and start adding little and keep whisking. You might not need all of the eggs.
The choux pastry batter is ready when it is glossy. Do a spoon test to check the consistency, grab a bit of batter on the spatula and let it drop. If it creates a V shape then its done. Also check if it hold shape running a finger across the batter. At this stage you can refrigerate the batter for 2 days.
Transfer to a piping bag. Squeeze out into desired length.
Bake in the preheated oven at 170*C for 20-25 minutes until golden.
If the eclairs have turned out well then they will be hollow inside.
Vanilla Pastry Cream (Creme Patissiere/Creme Pat)
Mix milk and vanilla essence and heat until it just reaches its boiling point.
Do not let it boil. Take it off the heat and add a ladle full of milk into the egg mixture and stir vigorously to avoid the scrambling of the egg. Continue until all the milk has been added.
Transfer the mixture back into the pot and cook on low flame, stirring continuous until the crème pat is nice and thick.
Transfer to a bowl and cover with a cling film to avoid skin forming on the crème pat.
Allow to cool to room temperature.
Chocolate Glaze
Bring sugar and water to boil and boil for 3-4 minutes until slightly thickened.
Take off the flame and add butter and chocolate.
Mix thoroughly until smooth. It might look a bit grainy when you first start mixing (because of the butter) but with continuous mixing for 3-4 minutes the glaze becomes smooth.
Assembly
Fill a piping bag with crème pat. Make a hole in the bottom of the éclair using the piping tip.
Start squeezing room temperature crème pat into the eclairs and stop when they feel filled and heavy.
Dip in slightly warm chocolate glaze. Allow to set.