How to Make Choux Pastry, No Guesswork Required

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