Preheat the oven to 425°F. Line baking sheets with parchment paper.
In a medium saucepan, combine the water, butter, salt, onion powder, thyme and pepper. Bring to a boil over medium-high heat: once the mixture boils remove the pan from the heat.
Add in the flour and stir until the flour is no longer visible in the mixture. Return the pan to medium heat and stir the dough constantly for 2-3 minutes: the mixture will become drier and will pull away from the sides of the pan.
Transfer the dough to the bowl of a stand mixer. Mix it on low speed for 2 minutes to cool it down—this is important because if the dough is too hot it will cook the eggs when you add them. Test the dough with your finger: if it's still too hot to touch let it sit for a few minutes longer.
Once the dough has cooled, add the eggs in one at a time and mix each at medium speed until incorporated. Touch the batter—when you pull your finger away a small peak should form.
Add in the grated Swiss cheese and mix the dough on low just until the cheese is incorporated.
Drop the dough by teaspoonfuls or use a small, 2 teaspoon-sized ice cream scoop to make one-inch balls on the prepared sheet. Or if you prefer, transfer the dough to a pastry bag with a large fluted tip and pipe it onto the prepared sheets.
Bake the gougères for about 18-20 minutes until they are puffed and golden brown.
Serve them warm if possible! If you are planning to fill them, allow them to cool before splitting them open to do so.
Makes about 40 Gougères.
Notes
The Gougères are delicious served on their own, or you can also use them to hold savory fillings like ham or chicken salad, or a dollop of Boursin herbed cheese.