Preheat the oven to 390°F (200°C).
Grease a baking dish with ½ tablespoon of olive oil.
Start by arranging the sliced tomatoes at the bottom of the greased baking dish.
Sprinkle ¼ of the chopped thyme, garlic, salt, and black pepper evenly over the tomatoes and drizzle with ¼ of the olive oil so they're lightly coated.
Layer the sliced eggplants on top of the tomatoes.
Arrange half of the sliced potatoes, followed by sliced zucchini. Sprinkle ¼ of the chopped thyme, garlic, salt, and black pepper
Layer the rest of the sliced potatoes, red pepper, and red onion.
Sprinkle remaining chopped thyme, garlic, salt, and black pepper evenly, and drizzle the remaining olive oil so everything is lightly coated.
Cover the baking dish with aluminum foil.
Place the covered dish in the preheated oven and roast for about 45-50 minutes, or until the vegetables are tender and lightly browned.
Once cooked, remove the foil and allow the vegetables to cool slightly before serving.
If the vegetables are not browned enough, roast them for another 10 minutes, until they are slightly charred.