Cook the bacon first in a medium-sized pan over medium heat until crispy.
Let drain on a paper towel, reserving bacon fat in the pan.
Place the onions into the bacon fat, season with the salt and pepper, cook on medium-low heat until soft and deep brown color, stirring often. About 45-50 minutes. Stir in the herbs. Set aside.
Preheat the oven to 450°F. Line a sheet tray with parchment paper, set aside.
Place the puff pastry onto a clean work surface. Unwrap it and cut out circles with a 2 ½ to 3-inch cookie cutter. Place them not touching on the prepared sheet tray.
Whisk the egg with the water in a small bowl.
Brush the tops of the pastry rounds.
Top evenly with the caramelized onions and bacon right in the center. Evenly sprinkle with the cheese.
Bake for 16 - 20 minutes until golden brown. Garnish with more parsley, optional. Serve immediately.
Notes
This recipe can easily be doubled.
They can be frozen, see above on how to do that.
Other herbs can be used if you'd like, see above on my suggestions.
Add a dipping sauce, some of my favorites are pesto, honey mustard, etc.
You can use any of your favorite bacon, our favorite is applewood smoked bacon.