Place water and butter in a pan and bring to a boil.
Turn off the heat and allow to cool for 1 minute. Whilst cooling, beat the egg and prepare 2 piping bags: one with the smallest and one with the largest tip nozzles.
Add the beaten egg to the pan a little at a time, till the mixture comes together. Transfer a little over ¾ of the mixture into the large nozzle bag, and the remaining mixture into the small nozzle bag.
Using the large nozzle bag, pipe 4 large teardrop shapes onto the baking tray. Bake for 10 minutes.
Meanwhile, on a second baking tray, using the small nozzle bag, pipe 4 elegant 'S' shaped swan necks. (Tip: At the top end, pipe the head of the swan, pulling the bag away sharply to make a pointed beak).
After 10 minutes, transfer the swan necks to the oven and bake for a further 8-10 minutes, with the teardrop shapes. (The choux pastry is ready when golden brown and puffed up)
Remove from the oven and allow to cool.
Assemble the swan as directed. Cut off the top third of one tear drop with a serrated knife, horizontally and lengthways, to create 2 wings. Fill with jam and whipped cream and position the wings and head as shown. Dust with icing sugar and decorate as desired.