Combine oil, water and salt in a saucepan and heat.
Bring a saucepan with water, oil and flour to a boil. Stir and melt the butter. Pour the flour into it and stir well so that no lumps form. Leave on the stove to heat for another 3 minutes and remove.
Let the dough cool. After this, add the eggs one at a time and mix them well into the dough. Place the finished choux pastry in a pastry bag, place the dough on a baking sheet in the form of small cakes.
Fill the prepared cakes with custard. The eclair can be topped with chocolate or sprinkled with powdered sugar.