Grill or fry the bacon until golden and crispy then transfer them to a plate.
Meanwhile put the spinach or kale in bowl and pour boiling water over it. Let it rest for 5 minutes, then drain.
Finely chop the onion, grilled pepper and tomatoes.
In a bowl, lightly whisk the eggs with the rosemary/oregano and salt & pepper.
Cut the bacon into small cubes. Squeeze the water out of the spinach, then finely chop.
Divide the chopped veggies and bacon between 2 silicon baskets or lightly oiled ramekins.
Pour over the egg mixture, then scatter the grated cheese on top.
Set the air fryer to 170°C or 340 F and “bake” the egg cups for 15-20 minutes. Allow the air to circulate properly - so put them on a shelf in the basket, if possible.
Let them cool in the cups, then turn them out onto a plate - if they are still a bit wet underneath, put them back in the air fryer, facing downwards, and cook for another 5 minutes or so.
Serve them warm or at room temperature.