Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper or lightly brush it with vegetable oil to prevent sticking.
Slice the eggplants into 1/4-inch thick rounds and arrange them in a single layer on the prepared baking sheet.
Bake the eggplant slices for about 20 minutes until they are golden around the edges and tender when pierced with a fork.
Remove the eggplant from the oven and let them cool for a few minutes. Meanwhile, spread some marinara sauce in the bottom of a baking dish.
Arrange a layer of baked eggplant slices over the sauce, overlapping slightly for even coverage.
Sprinkle a portion of shredded mozzarella and Parmesan cheeses over the eggplant layer, then add another layer of marinara sauce.
Repeat the layering process—eggplant, cheese, sauce—until all ingredients are used, finishing with a cheese layer on top.
Sprinkle dried oregano, salt, and pepper on top, then bake uncovered for about 20-25 minutes until bubbly and the cheese is golden.
Remove from the oven and let it rest for 5 minutes. Slice and serve warm, garnished with fresh herbs if desired.
