Preheat your oven to 350°F (175°C). Place the croissants on a baking sheet lined with parchment paper and lightly toast them in the oven for about 5-7 minutes until warmed and slightly crunchy.
In a medium bowl, whisk together the eggs, milk, salt, and pepper until well combined and frothy.
Heat a non-stick skillet over medium heat and add the butter. Once melted and bubbling, pour in the egg mixture. Stir gently with a spatula, cooking until the eggs are just set but still slightly creamy, about 3-4 minutes. Remove from heat and stir in the shredded cheese until melted.
In the same skillet, add the turkey or chicken sausage slices and cook until browned and heated through, about 3-4 minutes.
Split the toasted croissants in half. Layer the bottom half with the cheesy scrambled eggs, followed by avocado slices and cooked sausage (if using).
Pile a handful of fresh arugula or spinach on top for a vibrant and fresh crunch. Optionally, drizzle hot sauce for an extra kick.
Place the top half of the croissant on the sandwich and press gently. Serve immediately while warm, and enjoy your hearty breakfast!
Notes
Feel free to customize with your favorite cheese or add more vegetables.