Preheat the oven to 375°F (190°C).
Slice the eggplants into ½-inch thick rounds. Place them in a colander and sprinkle salt over the layers. Let them sit for about 30 minutes to draw out moisture.
Rinse the eggplant slices under cold water to remove excess salt and pat them dry with paper towels.
Set up a breading station: In the first shallow bowl, place the flour. In the second bowl, whisk the eggs. In the third bowl, place the breadcrumbs.
Dip each eggplant slice first into the flour, shaking off any excess, then into the egg, and finally coat it with breadcrumbs.
Heat olive oil in a large skillet over medium heat. Fry the breaded eggplant slices in batches until golden brown on both sides, about 4-5 minutes per side.
Use a slotted spoon to transfer the fried eggplant slices onto paper towels to drain excess oil.
In a 9x13 inch baking dish, spread a thin layer of marinara sauce at the bottom. Layer half of the fried eggplant slices over the sauce.
Sprinkle a portion of mozzarella and Parmesan cheese on top, along with half of the dried oregano.
Repeat the layering process with the remaining marinara sauce, eggplant, and cheeses. Finish with a final layer of cheese on top.
Cover the baking dish with aluminum foil and bake in the preheated oven for 25 minutes.
Remove the foil and bake for an additional 15-20 minutes, or until the cheese is bubbly and golden.
Allow the dish to cool for about 10 minutes before serving. Garnish with fresh basil leaves if desired.