Preheat your oven to 220°C (430°F). Gather a large rimmed sheet pan, rinse and dry all vegetables, then slice the eggplant and zucchini into 1-inch rounds, and cut the bell peppers into strips. Halve the cherry or heirloom tomatoes and set aside.
In a mixing bowl, toss the eggplant and zucchini with 1.5 tablespoons of olive oil, dried thyme, a pinch of salt, and pepper until evenly coated. Spread them out in a single layer on the sheet pan.
Place the sheet pan in the oven and roast for 15 minutes, until the vegetables start to turn golden and become tender around the edges.
Meanwhile, toss the bell pepper strips with the remaining 1.5 tablespoons of olive oil, a pinch of salt, pepper, and an extra dash of thyme if desired. After the initial 15 minutes, add the peppers to the sheet pan, spreading them around the other vegetables.
Continue roasting for another 15-20 minutes, until all vegetables are tender, caramelized, and slightly charred around the edges. Check periodically to avoid burning the garlic.
In the last 10 minutes of roasting, sprinkle the minced garlic evenly over the vegetables. Roast until fragrant and slightly roasted, about 10 minutes. If the garlic starts to burn, remove from the oven sooner.
Remove the sheet pan from the oven and gently stir in the halved cherry tomatoes. Let everything sit for 5 minutes to allow the tomatoes to soften and release their juices, creating a rustic sauce.
Taste the dish and adjust seasoning with additional salt and pepper if needed. Garnish with fresh basil or thyme leaves for a burst of herbal aroma.
Serve the roasted ratatouille hot or at room temperature directly from the pan, enjoying the tender, caramelized vegetables and smoky edges.
