In a saucepan, add the water, salt, sugar, and butter. Bring to a boil.
Once it reaches a boil, remove it from the heat, and add the sifted flour.
Next, put the saucepan back on the heat, and stir well for several minutes, stopping when you obtain a homogenous dough.
Then, remove from the heat, and incorporate the eggs, one by one.
Cover two baking sheets and scoop the mixture into a piping bag with a round nozzle.
To make the swans, on the baking sheets, pipe an éclair, as wide as 7 to 8 cm for the body. On the other sheet, for the neck and head of the swan, pipe an “S” shape with a smaller nozzle about 7 to 8 cm long but not larger than the body.
Then, with a brush, glaze them with the egg, and place the sheets in the oven for 25 minutes.
When done, remove them from the oven and place them on a wire rack to cool.
Once they are cooked and cooled, cut open the swan's body lengthwise (to about 2/3 height) and fill the body with pastry cream using the piping bag.
Next, cut the top of the body in half to create swan wings, but leave a few centimetres in the front to attach the neck and head. Pipe in the vanilla cream, sprinkle with powdered sugar, and enjoy!