Put softened butter, water and salt in a saucepan and boil briefly, stirring constantly. (The butter must be melted before boiling).
Take the saucepan off the heat, immediately add flour and mix briskly with a wooden wooden spoon until a large dough ball has formed.
Put the saucepan back on the stove and heat the dough, stirring and turning it with a wooden spoon, for about 1 - 2 minutes, until the dough comes off the bottom of the saucepan as a dumpling, leaving a white layer of starch.
Take the saucepan off the heat, transfer the dough to a clean mixing bowl and let it cool to lukewarm.
Stir eggs into the batter, one at a time, until it is shiny and clings to the wooden wooden spoon in peaks. It is best to whisk the last egg in a small bowl and add just enough of it to the dough until it has the right consistency. The batter should be creamy, definitely not runny or firm.
Pour the batter into a piping bag fitted with a round hole nozzle or star nozzle and pipe rings onto a baking sheet lined with parchment paper, leaving enough space between them.
Bake the choux pastry rings in a preheated oven at 190 °C for about 30 minutes until golden brown and let them cool.