Prepare the eggplant by generously salting both sides of the eggplant slices and laying them flat between sheets of paper towel. Let the eggplant sit like this for 30 minutes while you prepare the rest of the recipe ingredients.

Prepare a dredging station. Combine the breadcrumbs, parsley, Italian seasoning, garlic powder, onion powder, salt and black pepper in a shallow dish. Whisk the milk and mayonnaise together in a small bowl until smooth.

Pre-heat the air fryer to 400ºF.

Brush the excess salt from the eggplant slices and then coat both sides of each slice with the mayonnaise mixture. Dip the eggplant into the breadcrumbs, pressing the crumbs onto the eggplant to coat both sides of each slice. Place all the coated eggplant slices on a plate or baking sheet and spray both sides with olive oil. Air-fry the eggplant slices in batches for 15 minutes, turning them over halfway through the cooking time.

Once all of the eggplant has been browned, assemble the Panini. Generously brush one side of each slice of bread with olive oil. Place 2 slices of bread on a cutting board, oiled side down. Top each slice with a quarter of the mozzarella cheese and sprinkle with some Parmesan cheese. Divide the cooked eggplant between the two Panini, placing them on the cheese. Spoon the tomato sauce evenly over the eggplant and top with remaining mozzarella and Parmesan cheeses. Sprinkle with the chopped fresh basil and place the second slices of bread on top, oiled side up.

Place sandwiches onto a pre-heated contact grill or Panini press and close the lid, press down slightly to make sure bread will brown evenly. Grill for 10 minutes until bread is toasted and cheese is melted. Alternately, grill the Panini in a grill pan with a weighted press on top and flip it over halfway through cooking.

Return the finished Panini to a cutting board and let them rest for 1 to 2 minutes. Then, cut each Panini in half and serve immediately.