Preheat your oven to 375°F (190°C). While the oven is heating, dice the eggplant, sprinkle it with salt, and let it sit in a colander for 20 minutes to draw out excess moisture and bitterness. Rinse and pat dry.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the diced eggplant and cook until it starts to soften and brown, about 5-7 minutes. Transfer the eggplant to a large baking dish, and use the same skillet for the next step.

Add another tablespoon of olive oil to the skillet. Sauté the onions and bell peppers together for about 5 minutes, until they start to soften. Add the minced garlic and cook for another minute until fragrant. Add these to the baking dish with the eggplant.

In the same skillet, heat the remaining tablespoon of olive oil and sauté the zucchini rounds for about 4-5 minutes until lightly browned. Stir in the chopped tomatoes, and allow them to release their juices for 2-3 minutes. Season this mixture with salt, pepper, and thyme.

Transfer the zucchini and tomato mixture to the baking dish with the other vegetables. Add the bay leaf, and give everything a gentle toss to combine the flavours. Taste the mixture and adjust seasoning if necessary, adding more salt or pepper to suit your taste.

Cover the baking dish with aluminium foil and place it in the preheated oven. Let the ratatouille bake for about 45 minutes, allowing the vegetables to become tender and the flavours to meld together.

After 45 minutes, remove the foil and bake for another 15 minutes, allowing the vegetables to caramelize slightly. This step enhances the overall flavour of the dish. Remove the bay leaf before serving.

Serve the ratatouille warm, garnished with fresh basil leaves. This dish pairs wonderfully with crusty bread or as a side to roasted meats or fish. For a lighter meal, serve it over couscous or quinoa. Enjoy!