Salt the cod with sea salt and let rest for about 15 minutes
Slice the onion and crush the garlic
Add the olive oil to the skillet and gently fry the onions for 5 minutes before adding the garlic and cooking for a further 2-5 minutes
Wipe off the seasalt from the cod
Add the tomatoes and the cod to the pan and cook for a further minute. Season the cod with pepper and top with lemon slices
Add the spinach, chickpeas, wine and olives if using and spread around the pan
Put the dish in the air fryer or oven at 180C
Cook for 15-20 minutes (depending on the thickness of your fish), until you can see traces of white protein rising to the top of the fish and it is nicely opaque.
If necessary add a little water, wine or vermouth during cooking so that there is always liquid in the pan
Check and adjust the seasoning and serve with the remaining lemon cut into wedges on the side