Preheat your oven to 375°F (190°C).
Slice each croissant in half lengthwise and gently hollow out the center of each half to create a boat shape.
In a large mixing bowl, whisk together the eggs, milk, salt, pepper, and garlic powder until well combined.
Stir in the crumbled bacon, shredded cheddar cheese, and chopped chives if using.
Place the croissant halves on a baking sheet lined with parchment paper.
Carefully pour the egg mixture into each croissant boat, filling them about three-quarters full.
Bake in the preheated oven for 15-20 minutes, or until the egg is set and the tops are golden brown.
Remove from the oven and let cool for a few minutes before serving.