Prepare the donuts: boil the water with a pinch of salt and oil. When it boils, add the flour and mix vigorously until you get a ball of dough that comes off the bottom of the bowl. Let it cool. Incorporate the eggs one by one, mixing very well after each one. Bake with a teaspoon or sprinkle on the baking sheet, then put in the oven until golden. Leave to cool.
Cream: boil the milk. Rub the yolks with the sugar, vanilla and starch, and when the milk is hot, add it in a thin thread over the composition. Put everything on low heat and stir until it thickens. Then mix with whipped cream.
The cooled donuts are cut in half and filled with cream. Powder with sugar or glaze with chocolate.