Pearl or Crystal sugar (Pearl sugar is available in the US from King Arthur and on Amazon. In Paris, I buy mine at G. Detou.)
1. Preheat the oven to 425 degrees (220 C.) Line a baking sheet with parchment paper or a silicone baking mat. (Depending on the size of your baking sheets, it may take two.)
2. Heat the water, salt, sugar, and butter in a small saucepan, stirring, until the butter is melted. Remove from heat and dump all the flour in at once. Put the pan back on the heat and stir rapidly until the mixture is smooth and pulls away from the sides of the pan.
3. Allow dough to cool for two minutes, then briskly beat in the eggs, one at a time, until smooth and shiny.
4. Using two spoons, scoop up a mound of dough with one spoon roughly the size of an unshelled walnut, and scrape it off with the other spoon onto the baking sheet. You can also use a pastry bag fitted with a plain 1/2-inch tip and pipe them.
5. Place the mounds evenly-spaced apart on the baking sheet(s). Brush the top of each mound with some of the egg glaze then press pearl sugar crystals over the top and sides of each mound. Use a lot. Once the puffs expand rise, you’ll appreciate the extra effort (and sugar.)
6. Bake the cream puffs until puffed and well-browned, about 25 to 30 minutes. If they get too dark midway through baking, lower the heat of the oven to 375ºF (190ºC) and continue baking.
(If you want to make them crispier, you can poke a hole in the side with a knife after you take them out of the oven to let the steam escape.)