Preheat the oven to 425°F (220°C). Line the sheet pan with parchment paper and lightly oil it.

Slice the eggplant into 1/2-inch thick rounds. Cut a center hole from each round, leaving a narrow eggplant border.

Arrange the hollow eggplant rounds on the prepared sheet pan. Finely chop the removed eggplant centers.

Heat 3 tablespoons olive oil in the frying pan over medium-high heat. Sauté the chopped eggplant and yellow onion for 10 to 12 minutes until tender.

Add the Roma tomato, garlic, salt, and black pepper to the frying pan. Sauté for 3 to 4 minutes until the tomatoes soften.

Remove the vegetable mixture from the heat. Let it cool for 10 minutes.

Transfer the cooled vegetable mixture to the mixing bowl. Stir in fresh basil, dried oregano, mozzarella, and Parmesan cheese.

Add the egg to the filling. Mix until the egg is fully incorporated.

Spoon the filling into the hollow eggplant rounds. Fill each round completely.

Sprinkle breadcrumbs over the filled rounds if using. Brush the eggplant borders with additional olive oil.

Bake for 25 to 27 minutes. Serve when the cheese is golden, melted, and bubbling.

Brush the edges with more olive oil, then place into the oven for 25-27 minutes.