- Preheat the oven to 375°F (190°F) and line 2 baking trays with parchment paper.
- Place the bacon in the bowl of a food processor and pulse until it is the texture of crumbs. Remove and set aside (no need to wash the food processor bowl).
- In a medium saucepan, bring the milk and butter to a simmer over medium heat. Add the flour all at once and use a wooden spoon to vigorously stir the paste mixture for about 2 minutes, until it pulls away from the pan. Scrape into the food processor bowl and let sit to cool for 5 minutes.
- Break the eggs into a cup. While pulsing the food processor, add the eggs about 1 at a time, quickly pulsing to incorporate before adding the next. Scrape down the bowl between additions.
- Add the Gruyère, Parmesan, chili powder and cooked bacon and pulse well until the cheese is blended into the paste. Spoon this mix- ture (it will still be warm) into a piping bag fitted with a large plain tip, or use a small ice cream scoop.
- Pipe or scoop the batter into 1 1⁄2-inch (3.5 cm) rounds on the pre- pared baking trays, 1 1⁄2 inches (3.5 cm) apart. If the rounds have little points from where you lifted up the piping bag, dip your finger in cool water and pat them down.
- Brush the gougères with the egg wash and then bake for 25 to 30 minutes, until they are a rich golden brown and are light when lifted off the tray. Allow the gougères to cool for at least 10 minutes on the tray before eating. They are best enjoyed warm but can be eaten at room temperature.
These puffs need to be piped and baked while the dough is still fresh and warm, but once baked, they freeze incredibly well. You can freeze them, well wrapped, for up to 3 months, and then re-warm on a tray in a 325°F (160°C) oven for 12 to 15 minutes. You can store baked puffs in an airtight container at room temperature for 1 to 2 days. Do not refrigerate them or they will dry out.