Preheat oven to 400 Â°F (200 Â°C).
Score flesh of eggplant in crisscross pattern. Brush with oil and place, skin-side up, in roasting pan. Cook 40 minutes in oven.
Remove flesh from skin, chop flesh and set aside.
Heat remaining oil in frying pan over high heat. Add onion and garlic; mix and cook 6 minutes. Add tomatoes, zucchini and basil. Season and cook 20 minutes over medium heat, stirring occasionally.
Add chopped eggplant and mix well. Add half of cheese and pinch of sugar. Mix and season to taste.
Reduce oven heat to 375 Â°F (190 Â°C).
Transfer mixture to baking dish. Top with remaining cheese and cook 20 minutes in oven.