Heat the oven to 425°F. Line two rimmed baking sheets with parchment paper and brush with 1 tablespoon of the olive oil.

Put the all-purpose flour in one shallow bowl. Beat the eggs and water in a second. In a third, combine the plain panko breadcrumbs, 1/4 cup of the finely grated vegetarian hard cheese, dried oregano, garlic powder, fine salt, and black pepper.

Pat the eggplant rounds dry. Coat each round lightly in flour, dip in egg, then press into the breadcrumb mixture. Arrange in one layer on the prepared sheets and drizzle with the remaining 2 tablespoons olive oil.

Bake for 25 to 30 minutes, turning the rounds and swapping the tray positions halfway through, until golden and tender when pierced with a fork.

Lower the oven to 400°F. Spread 1 cup tomato marinara sauce in the baking dish. Add half the eggplant, half the mozzarella, and another cup of sauce. Repeat with the remaining eggplant, sauce, and mozzarella. Sprinkle with the remaining 1/4 cup finely grated vegetarian hard cheese.

Bake uncovered for 20 minutes, until the sauce bubbles around the edges and the cheese melts. If the cheese browns too quickly, cover loosely with foil.

Rest for 10 minutes so the layers settle. Scatter the fresh basil leaves over the casserole and serve.