Preheat the grill to medium-high heat. Brush the eggplant slices with olive oil.
Grill the eggplant slices for 3-4 minutes per side, until lightly golden brown and tender.
In a large skillet over medium heat, heat the remaining olive oil. Add the onion and garlic and cook until softened, about 5 minutes.
Add the diced tomatoes, oregano, salt, and pepper and simmer for 10 minutes.
Preheat the oven to 375°F.
In a 9x13-inch baking dish, layer half of the eggplant slices. Top with half of the tomato sauce and half of the parsley. Sprinkle with half of the mozzarella and parmesan cheeses.
Repeat with the remaining eggplant slices, tomato sauce, parsley, and cheeses.
Bake for 25 minutes, or until the cheese is melted and bubbly.
Serve hot.
Interesting Facts
The eggplant is a member of the nightshade family, related to tomatoes, peppers, and potatoes.
Eggplant Parmesan is often referred to as Melanzane alla Parmigiana in Italian.
The dish originated in the region of Campania, in southern Italy.
The dish is also popular in other parts of the world, including the United States.