Step 1

In a 3-quart stainless-steel saucier or saucepan, combine water (or milk), butter, sugar (if using), and salt.

Step 2

Set over high and and cook until liquid comes to a rolling boil and butter has fully melted, about 2 minutes (the small butter cubes should be fully melted just about at the same time the liquid hits a strong boil).

Step 3

Remove from heat and add flour. Using a wooden spoon or stiff silicone spatula, thoroughly mix in flour until no lumps remain (make sure to hunt down and smash out any stubborn ones).

Step 4

Return saucepan to medium-high heat and cook, stirring very frequently, until dough registers 175°F (80°C) on an instant-read thermometer; if you don't have a thermometer, other signs the dough is ready include a thin starchy film forming all over the inside of the saucier and the dough pulling together into a cohesive mass.

Step 5

To use a stand mixer: Transfer dough to a stand mixer fitted with the paddle and beat at medium speed until dough registers 145°F on an instant-read thermometer (you need the dough cool enough that it doesn't cook the eggs when they hit it).

Step 6

Add eggs one at a time, making sure each is fully beaten into the dough before adding the next; it can help to start the mixer at medium-low speed for the first egg and then increase the speed to medium once the choux batter begins to develop.

Step 7

Scrape down sides of mixer bowl, then mix once more at medium speed just to ensure the choux batter is fully mixed, about 5 seconds.

Step 8

Alternatively, to incorporate eggs by hand: Let dough cool in saucepan, stirring frequently, until it registers 145°F on an instant-read thermometer. Add eggs 1 at a time, stirring well between additions until each egg is fully incorporated before adding the next, until a smooth, shiny paste forms.

Step 9

Use choux right away, or hold at room temperature for up to 2 hours before using; how you use the choux will depend on the application, though it’s important to prevent a skin from forming, either by transferring the choux right away to a pastry or zipper-lock bag and keeping it sealed, or pressing plastic wrap directly against the choux’s surface.