Put butter and water in a deep saucepan and bring to boil slowly. (Do not allow water to boil before the butter has melted.)
Remove saucepan from heat. Add in flour and salt. Place saucepan over the heat and stir quickly until a ball is formed and the dough comes away from the sides of the saucepan. Remove the saucepan from the heat and leave to cool slightly (approximately five minutes).
Beat in eggs one at a time until the dough becomes stiff.
Place teaspoonfuls of the dough on a greased baking sheet. Bake in a preheated oven at 200 degrees C for 10 minutes.
Reduce the temperature to 180 degrees C and continue to bake for 15 minutes, then leave the puffs to cool in the oven. Fill the empty shells with custard cream or any desired cream.