First, preheat your oven to 425°F (220°C). It’s crucial to have a hot oven for that puffing magic!

In a saucepan, combine water, butter, and a pinch of salt. Heat over medium until the mixture is boiling. Once it reaches a rolling boil, remove it from the heat and stir in the flour all at once. Mix vigorously until a smooth ball forms. Place the saucepan back on the heat for another minute, stirring constantly to dry out the dough slightly.

Next, transfer the dough to a mixing bowl. Allow it to cool for a few minutes. This is important since you don’t want to scramble your eggs! Once it’s slightly warm but not hot, add in the eggs, one at a time, mixing thoroughly after each addition. After all eggs are incorporated, stir in the nutmeg, mustard, pepper, and grated Gruyère cheese until well combined.

Using a spoon or a piping bag, dollop or pipe the dough onto a baking sheet lined with parchment paper. Make sure to leave some space between each puff since they will expand while baking!

Brush the tops with the egg yolk wash and sprinkle a little extra Gruyère cheese on top. This step gives them that golden-brown finish and an extra cheesy crust.

Place the baking sheet in the preheated oven. Bake for about 20-25 minutes, or until the gougères are puffed and golden. Keep an eye on them; you want them to rise nicely without burning!

Once they’re out of the oven, let them cool for a minute. But honestly, who can resist diving right in? They are best served warm but are still delightful at room temperature.