Pour the water and oil in a pot and leave them to come to a boil. Once they do, add the flour and stir for a few min. to obtain a thick mixture. Take the mixture off the stove and leave to cool.
Once cooled, start adding the eggs 1 by 1, while stirring well after each one. You're going to get an even thicker and sticky dough.
Put baking paper at the bottom of a baking form, scoop from the mixture with a spoon and arrange the eclairs with some space in between them. After you place the final eclair, put the form in a preheated 392°F (200 °C) oven and bake about 30 min.
While the eclairs are baking, prepare the cream. Pour the milk in a pot and leave it to boil. Once ready, add the eggs beaten with the sugar and then the flour, diluted with a little water. Stir nonstop for a few min. and add the butter.
Stir well once more. Add the vanillas. Take the eclairs out of the oven and leave them to cool. Once ready, cut them carefully down the middle and put the cream. You can sprinkle the ready eclairs with powdered sugar.