Preheat the oven to 375°F (190°C).
In a large skillet, heat the olive oil over medium heat.
Add the garlic and onion, sauté for about 2 minutes, until softened.
Add the sliced eggplant, zucchini, bell pepper, and mushrooms to the skillet.
Cook for 5-7 minutes until the vegetables are slightly tender.
Season the vegetables with dried basil, oregano, salt, and pepper.
Stir in the tomato sauce and mix well.
Transfer the vegetable mixture to a casserole dish, spreading it evenly.
Bake in the preheated oven for 25-30 minutes or until the vegetables are tender and the top is lightly browned.
Garnish with fresh basil before serving.