Preheat the oven to 375°F. Grease or line a baking tray with parchment paper. Measure and prep all ingredients.
Make the marinara sauce. In a pot over medium heat, cook onions, diced tomatoes and olive oil.
Add the basil, oregano, garlic, salt, pepper and tomato sauce to the pot and simmer until slightly thickened, about 15 minutes. Set aside.
Slice the eggplant. In another bowl, combine the panko, basil, oregano, garlic, salt and pepper.
Add a thin layer of vegan mayonnaise on both sides of the eggplant. Coat both sides with the panko mixture.
Arrange the eggplant on the baking tray and bake at 375°F for 15 minutes, or until tender and golden brown. Ladle half of the marinara sauce in a baking dish and top with the cooked eggplant.
Ladle the remaining marinara sauce on top.
Top with vegan cheese and garnish with basil if desired. Bake at 400°F for 5-10 minutes until the cheese melts and turns golden brown.
Remove from the oven and garnish with basil. Serve hot with a side salad. Enjoy!