Grease a 9-by-13-inch baking dish with 1 tablespoon of the olive oil. Rub the sides of the dish with the garlic.
In a large, nonstick skillet, heat 2 tablespoons olive oil over medium-high heat. Swirl the garlic in the pan for 1 to 2 minutes or until fragrant; discard the garlic. Add the red pepper and onion and cook, stirring frequently, until beginning to soften, about 5 minutes.
Reduce the heat to medium and continue cooking, stirring occasionally, until extremely soft, 7 to 8 more minutes. Season with salt and pepper, and remove from the heat. Stir in half of the chopped basil and let cool slightly. Preheat the oven to 425°.
Spread the pepper-onion mixture in the bottom of the baking dish. Arrange the remaining vegetables so they’re standing up in the dish in 3 long rows, repeating the following pattern: 1 eggplant slice, 1 tomato slice, and 1 zucchini slice. Season the vegetables generously with salt and pepper, sprinkle with the remaining chopped basil, and drizzle with the remaining 2 tablespoons olive oil.
Cover the baking dish with foil and bake for 30 minutes. Remove the foil and bake for 30 more minutes, or until the vegetables are beginning to brown. Let cool slightly and serve.
Recipes adapted from Modern Potluck (Clarkson Potter)
Makes one 9-by-13-inch baking dish