With a sharp knife cut the vanilla bean in half lengthwise, and using the dull side of the knife carefully scrape down all the small seeds.
In a small pot, whisk the milk, half of the sugar and the vanilla seeds together and heat to low temperature, mixing constantly by hand.
In a small bowl, beat the rest of the sugar along with the salt, the egg yolks and the corn starch. Beat in a little of the milk mixture, this will help the mixture temper.
Pour the egg yolk mixture over the milk mixture and cook to medium heat for about 3 minutes, stirring nonstop until a thick cream forms.
Take away from the heat and stir in the butter. Cover the cream with plastic wrap (which has to directly touch the surface of the cream, otherwise a custard will form) and fridge for 1 hour.
After that time, incorporate the whipped cream carefully using a rubber spatula and refrigerate for 30 more minutes.
Put the cream in piping or pastry bag with a small tip and fridge until needed.
For the dough:
Preheat the oven to 400°F.
In a medium pot combine water, milk, butter, sugar and salt. Heat it to medium-high heat and cook until it boils, for about 3 minutes.
Mix in the flour with a rubber spatula until a soft dough forms and starts to separate from the sides of the pot.
Lower the temperature to low heat and cook the dough for 2 min. constantly mixing with the spatula.
Take away from the heat and let rest for 3 min.
Add in the eggs, one by one, mixing after each addition (it will seem like the mixture will never fully integrate, but it is important to keep mixing until you get a soft, bumpless dough).
Put the doguh in a pastry bag with a big star tip and, on baking sheets previously lined with parchment paper, form the eclairs, making them to be about 4 inches long (10cm) and 3/4 inch (2 cm) wide.
Bake at 400°F for 10 minutes, lower the temperature to 360°F and bake for another 15-20 minutes. Once the eclairs are ready, take them out of the oven and make a small hole on each on the side with a wooden stick (this will let the vapor inside get out).
Let the eclairs cool down before using them.
For the chocolate ganache and to assemble it:
For the chocolate ganache, place the chocolate chips in a bowl. Heat to medium the whipping cream in a small pot for about 1 min. until it starts to boil. Pour the cream over the chocolate, let it sit for 1 min. and then mix until you get a fully integrated ganache.
Now, using the wooden stick again, make three holes on the back side of each eclair and fill them with pastry cream.
Cover each eclair with some chocolate ganache and let them sit for 10 minutes before eating.