Preheat the oven to 200°C / 400°F.
Lightly grease the bottom of a baking dish with nonstick cooking spray or butter.
Slice each croissant horizontally through the middle.
Arrange the five bottom halves of the croissants in the prepared baking dish.
Layer each croissant with cheese followed by sliced turkey.
Crack the eggs into a bowl. Add salt, black pepper, and milk and whisk until well combined.
Slowly pour the egg mixture evenly over the croissants.
Place the croissant tops over each sandwich.
Bake uncovered for 20–25 minutes, or until the eggs are completely set and cooked through in the center.
If the croissant tops begin browning too much before the eggs are finished cooking, loosely tent the tops with foil toward the end of the baking time.
Remove from the oven and allow the sandwiches to cool for a few minutes before serving.