When properly baked, the puffs should have a firm but not crusty exterior, and a moist but airy center.
- 6 tablespoons unsalted butter, cut into 1" pieces
- 1 tablespoon granulated sugar
- 6 large eggs, room temperature
- Pearl sugar (for serving; optional)
- Softly whipped, lightly sweetened cream (for serving; optional)
- A ½"-diameter pastry tip and a pastry bag
Preheat oven to 425˚. Line a rimmed baking sheet with parchment paper. Fit a large pastry bag with a plain ½" tip.
Heat milk, butter, granulated sugar, salt, and ½ cup water in a medium saucepan over medium, stirring occasionally to melt butter. As soon as butter is melted, add flour all at once and stir with a wooden spoon, carefully at first to incorporate, then vigorously, until dough forms a single mass. Continue stirring, slapping dough against sides of saucepan with spoon, until dough leaves a thick film on bottom of pan and pulls away from sides, about 3 minutes (the important thing here is to cook the flour and dry out the dough). Transfer to a medium bowl and let rest 3 minutes.
Using a wooden spoon, mix 5 eggs into dough one at a time, making sure to completely incorporate each egg before adding the next. Dough will look broken at first, then homogenized. The final texture should be smooth, glossy, and somewhat stretchy.
Spoon dough into prepared pastry bag. Holding bag at an angle so the tip is just touching the prepared baking sheet on one side, gently start to squeeze out dough. Without moving the tip (this will help shape a perfect circle), pipe until you have a 1½" round (you can trace circles on the back of the parchment for extra accuracy). Repeat, staggering rounds and spacing 2" apart.
Beat remaining egg in a small bowl until no streaks remain and lightly brush tops of dough. Sprinkle with pearl sugar, if using. Bake 15 minutes, then lower heat to 350˚. Continue to bake until puffs are deep golden brown all over and sound hollow when tapped on the bottom, 15−20 minutes.
Remove chouquettes from oven; turn oven off. Poke a small hole in the bottom of each puff with a paring knife and place, hole side up, on baking sheet. Return to still-hot oven, propping door open with a wooden spoon. Let dry out and cool, 30–35 minutes.
Serve chouquettes plain or use a serrated knife to cut tops off and spoon or pipe whipped cream into bottom half.
Do Ahead: Dough can be made 1 day ahead. Transfer to pastry bag and chill.
Variation: Herby Gougères: After adding eggs to dough, mix in 1 cup grated Gruyère, 1 Tbsp. finely chopped fresh chives, and 1 tsp. finely chopped fresh rosemary. Top each puff with a pinch of grated Gruyère before baking.