Preheat your oven to 190°C.
Bring 1 cup water to a boil in a saucepan.
Add the butter to the water and stir until it is melted.
Add the flour and salt all at once to the water mix.
Stir until a ball is formed.
Remove from heat, and add 1 egg. Beat. Let stand for 5 minutes.
Add the remaining eggs 1 at a time, and beat after each addition.
Let stand for 10 minutes.
After they have cooled completely you can put the filling of your choice.