Preheat your oven to 200°C (390°F). Slice the eggplant into 1/4-inch thick rounds, keeping the slices uniform for even roasting.
Thinly slice the zucchini into similar 1/4-inch rounds, and set aside. Slice the tomatoes into rounds as well, keeping all vegetables ready for layering.
Drizzle olive oil over the bottom of your baking dish, spreading it evenly to prevent sticking and aid caramelization during baking.
Start layering: arrange eggplant slices in a single layer on the baking dish, slightly overlapping if needed.
Add a sprinkle of sliced garlic and thyme over the eggplant layer, then drizzle a little olive oil.
Layer zucchini slices on top of the eggplant, overlapping slightly to cover the surface.
Sprinkle more garlic and thyme, then drizzle with olive oil again to build flavor layers.
Place a layer of tomato slices on top of the zucchini, slightly overlapping to create a colorful pattern.
Season the top with salt and black pepper, then drizzle with a final splash of olive oil.
Tightly cover the dish with aluminum foil and bake for 30 minutes, allowing the vegetables to soften and release their juices.
Remove the foil and continue baking for an additional 20-25 minutes, until the edges are lightly golden and bubbling.
Let the ratatouille rest for 5-10 minutes outside the oven, so the juices settle and flavors deepen.
Garnish with fresh basil leaves, tear them into pieces, and serve warm. Enjoy the tender, caramelized medley that’s bursting with roasted herb and vegetable flavors.