Cook the sausage patties in the air fryer at 350°F (175°C) for 10 minutes
meanwhile: preheat the oven to 350°F (175°C) and lightly grease a baking dish with non-stick spray
Whisk the eggs, milk, salt, and pepper in a medium bowl until fully combined
Heat 1 tbsp of butter in a skillet over medium-high heat
Add the egg mixture and cook, stirring occasionally, until scrambled and cooked through
Slice the croissants in half and place the bottom halves in the prepared baking dish
Layer spinach over each croissant bottom
Spoon scrambled eggs evenly over the spinach
Add a sausage patty and a slice of cheese to each sandwich
Place the croissant tops over the layers
Melt the remaining 1 tbsp of butter in the microwave
Brush melted butter over the tops of the croissants
If using it sprinkle each with everything bagel seasoning
Bake for 10 minutes or until croissants are golden and cheese is melted