Preheat oven to 400F (204C) and line two large baking sheets with parchment paper.
Bring the water, salt and butter to a full boil over medium-high heat.
Add the flour, and use a wooden spoon to stir as you cook for about 2 minutes until you have a smooth dough that cleans the sides of the pan.
Remove from the heat and place the cooked dough (pande) in a large bowl, and beat using the paddle attachment to cook to room temperature.
Add the beaten eggs in four additions. Once you added the third addition, turn the mixer off, dip the attachment or your wooden spoon into the paste, and lift it facing down. If it makes a "V" shape then it is ready, if not add the remaining eggs.
Fill a large pastry bag fitted with a round or a rosette tip and pipe 1-2 inch circles, leaving 3 inches gap between each round.
Bake over the lower oven rack for 10 minutes, then reduce the temperature to 375F (190C), for additional 12 minutes.
Turn the oven off and leave the pastries to cool in the oven for 20 minutes before opening it.
Cool completely before filling.