In a large pot of boiling salted water, cook the large pasta shells to al dente, then drain and rinse with cold water, drain well again. Set aside.
While pasta is cooking, in a medium-sized frying pan add 3 tablespoons of olive oil, diced eggplant and 1/2 teaspoon of salt. Cook on medium heat, stirring occasionally till golden. Remove to a medium-sized bowl and toss with parmesan. Set aside.
While the above are cooking, in another medium-sized frying pan add 2 tablespoons of olive oil, diced tomatoes, garlic, basil, oregano, 1/4 teaspoon salt and hot pepper flakes if desired. Cook on medium heat, after 10 minutes squish with a fork and continue to cook until thickened.
In a medium baking dish, drizzle lightly with olive oil, fill the shells with a teaspoon or 2 of the eggplant mixture, top with 2 or 3 cubes of mozzarella, place in baking dish, then finish by covering with the tomato sauce,drizzle with 1 tablespoon of olive oil and sprinkle with 2 or 3 tablespoons of grated parmesan cheese. Bake in a 375 degree oven for approximately 15-20 minutes (till cheese melts). Serve immediately, top with freshly chopped basil leaves. Enjoy!