Put butter, water and salt together in a saucepan and bring to the boil, stirring constantly. Make sure that the butter melts before it boils.
Remove the saucepan from the heat, immediately add flour and mix briskly with a wooden wooden spoon to form a dough ball.
Put the saucepan back on the stove and heat the dough, stirring constantly, for about 2 - 3 minutes, until it comes off the bottom of the saucepan as a dumpling, leaving a white layer of starch there.
Take the saucepan off the heat, transfer the batter to a clean mixing bowl and let it cool to lukewarm.
Add eggs (except the last one) to the batter one at a time, mixing each time to make a homogeneous batter. Beat the last egg in a small bowl to combine the whites and yolks, and add it to the dough in small amounts, a little at a time, stirring it each time until it has absorbed the amount of egg. You need to add as much of the egg to the dough until it shines and sticks in peaks to the wooden cooking spoon. For this, you might not use the last egg completely, or you might need a small amount of one more egg.
Fill the choux pastry into a piping bag with a round, approx. Ø 8 mm hole nozzle and pipe either on a baking mat or on a baking tray lined with baking paper three circles of the pastry, which are approx. Ø 23, 20 and 17 cm in size, so that the smaller circle always lies in the larger one and has about 3 cm distance from it (see pictures at the top of the article). To do this, you can either draw the circles on the baking paper beforehand with a pen or use a silicone mat with measurement.
Bake the choux pastry rings in a preheated oven at 190 °C for about 30 minutes and let them cool down afterwards.