Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper. Arrange the sliced eggplant in a single layer on the sheet, then brush or spray with olive oil. Roast for about 20-25 minutes until golden around the edges and tender when pierced with a fork.
Meanwhile, prepare the tomato sauce by heating a tablespoon of olive oil in a saucepan over medium heat. Add the minced garlic and cook until fragrant, about 30 seconds. Pour in the crushed tomatoes, add balsamic vinegar, and season with salt and pepper. Let simmer gently for 15 minutes, stirring occasionally, until slightly thickened and flavorful.
Once the eggplant slices are roasted, remove them from the oven and reduce the oven temperature to 375°F (190°C). Spread a thin layer of tomato sauce in the bottom of a baking dish. Arrange a layer of eggplant slices over the sauce, then sprinkle with shredded mozzarella and Parmesan cheese. Repeat layering, finishing with a cheese layer on top.
Place the assembled dish in the oven and bake for about 20 minutes, or until the cheese is bubbly and golden brown around the edges. The house will fill with a savory aroma as the cheese melts and the dish heats through.
Remove the dish from the oven and let it rest for a few minutes to allow the cheese to set slightly. Then, ladle some of the remaining tomato sauce over the top for extra flavor and serve hot, garnished with fresh herbs if desired.
