• Heat the olive oil in a large skillet over medium heat.
• Add the chopped onion and sauté for 3 minutes until softened.
• Stir in the garlic and cook for 1 minute.
• Pour in the tomato passata and add about ¼ cup water to rinse the bottle.
• Season with salt and black pepper.
• Simmer over medium-low heat for 30–40 minutes, stirring occasionally, until thick and rich.

Prepare the Eggplants

• Preheat the oven to 430°F (220°C).
• Line three baking trays with parchment paper.
• Wash and dry the eggplants, then remove the stems.
• Slice into ¼-inch thick rounds.
• Arrange the slices in a single layer on the trays.
• Brush with olive oil and season with salt.
• Bake for about 25 minutes until golden brown, rotating trays if needed for even cooking.

Assemble the Eggplant Parmigiana

• Reduce oven temperature to 350°F (180°C).
• Spread a thin layer of tomato sauce on the bottom of a casserole dish.
• Arrange the first layer of roasted eggplant slices.
• Spoon over some tomato sauce.
• Sprinkle with parmesan cheese, mozzarella, and basil leaves.
• Repeat the layering process three more times, creating four eggplant layers total.
• Finish the top layer with extra tomato sauce, mozzarella, and parmesan. Do not add basil to the final layer.

Bake

• Bake the Eggplant Parmigiana for 30 minutes until bubbly and golden.
• Allow it to rest for at least 15 minutes before slicing.
• Garnish with fresh basil and serve.