Slice the eggplant into 1/2 inch slices (you want to try and get 8 slices). Place eggplant slices on a baking sheet and sprinkle both sides with coarse sea salt. Allow the eggplant to sweat for 10 minutes by simply letting it just sit on the pan with the salt on it. Afterwards firmly pat each side of the eggplant slices with a paper towel to soak up the moisture. Brush off all the sea salt.
In a shallow wide bowl mix together the panko bread crumbs, Italian seasoning, garlic salt and 1 Tbsp of the parmesan cheese. Crack the egg in another bowl and beat until combined. Then place the flour on a small plate. Bread the eggplant by first coating both sides in flour, dip in the egg, and then in the breadcrumbs so that it is fully coated on both sides. Place in the basket of your air fryer. Depending on the size of your air fryer you will probably need to cook in 2 batches.
Spray both sides of the eggplant with oil. Then cook in the air fryer for 8-10 minutes until crispy and golden brown. Repeat with any remaining eggplant slices.
If you are using chicken cut two chicken breasts in half length wise. Pound down chicken so it's a thinner cutlet. Bread the same way you would the eggplant. Spray with oil and then cook in the air fryer for roughly 10-15 minutes until cooked.
In an 8x8 baking dish cover the bottom with a thin layer of marinara sauce. Place 4 of the eggplant slices in the dish. Put a spoonful of marinara on each eggplant slice and then top with a slice of mozzarella. Place a second slice of eggplant on top and then repeat layering marinara sauce and mozzarella. Sprinkle the top with parmesan cheese.
Bake at 400 F for 10 minutes. Increase oven temperature to broil and cook for 6 more minutes until bubbly and starting to brown. Allow to cool for a few minutes and then serve alongside pasta with more marinara sauce or a salad.
To reheat leftover eggplant I recommend doing so in a toaster over on bake at 400 F for a few minutes so it stays crispy.