Bring water to boil, add in salt and sugar plus the butter, stir to melt completely
Once your butter dissolved, turn heat to low and add in flour. Stir in quick motion as mixture will be thickened as shown on the picture. Take off from heat.
Once dough is off heat, let cool for 8-10 minutes, until warm to the touch. Then using electric mixer, mix in the egg, one egg at a time.
Place dough (or batter it became) into a piping bag with any tip you prefer, star or even round. You can even drop it by tablespoon (depending the size you wish to make). If you are good in piping, as in making the size equally big, by all mean, pipe away, onto a greased sheet. If not, you can pipe batter onto muffin tins, so they would bake the same size each time. Don't forget to grease the muffin tins as well. Bake in 395 F for 25 minutes. During baking time, do not, I repeat, DO NOT open the oven door whatsoever, or they will collapse once taken out of the oven.
Once cooked, take out of oven, and onto the cooling rack they go.