While gruyère is traditional, other sharp, nutty cheeses can be substituted (sharp cheddar, like Cabot clothbound, would be particularly lovely).
About 40 (1 1/2-inch) gougères
- 1 cup water
- 8 tablespoons unsalted butter
- 1/2 teaspoon kosher salt
- 1/4 teaspoon granulated sugar
- 1 teaspoon dry mustard
- A pinch of cayenne pepper
- 1 cup (5 ounces) all-purpose flour
- 2 large eggs
- 2/3 cup (2 1/2 ounces) grated gruyère cheese
Preheat the oven to 375ºF. Line two half-sheet pans with parchment paper.
In a medium (preferably not nonstick) saucepan heat the water until steaming. Add the butter, salt, sugar, mustard, and cayenne pepper. Lower the heat to medium-low and cook, stirring occasionally, until the butter has completely melted.
Slowly add the flour to the hot liquid while stirring vigorously with a wooden spoon. Keep stirring until the flour is completely incorporated, and the mixture comes together into a tacky ball that pulls away from the sides of the pan when stirred.
Transfer the dough to the bowl of a stand mixer and beat in the eggs, one at a time, until they're absorbed by the batter and it's smooth, sticky, and waxy in appearance. Fold in the gruyère.
Fill a pastry bag with the gougère dough, and pipe one-inch swirls of dough onto the parchment-lined pans. Using damp fingertips, gently smooth down any spikes (from where the pastry bag was lifted up) in the dough, so that they don't get too brown.
Bake for 30 to 35 minutes, or until they've puffed up and are lightly brown on top. After they've cooled for a couple minutes, use the tip of a very sharp knife to poke a small slit in the side of each gougère to release steam and prevent them from turning soggy. Serve warm (or rewarm in the oven before serving, if they're cool).