Part 1: Preparing the Eggplant – The Foundation of Flavor

This is the most critical stage to prevent a bitter or soggy final product. Do not skip the salting step!

1. Slice the Eggplant: Wash and dry the eggplants. Trim off the top stem and the very bottom. Using a sharp knife, slice the eggplant into uniform ½-inch thick rounds. Uniformity is key for even cooking and stable stacking.
2. Salt and Sweat: Arrange the eggplant slices in a single layer on baking sheets lined with paper towels (you may need two). Sprinkle both sides of each slice generously with coarse sea salt.
3. Let it Rest: Let the eggplant sit for at least 30 minutes, or up to an hour. You will see beads of moisture forming on the surface. This process, known as “sweating” or “de-gorging,” draws out excess water and any potential bitterness from the eggplant.
4. Rinse and Dry: Once rested, thoroughly rinse the eggplant slices under cold water to remove all the salt. Then, use paper towels or a clean kitchen towel to pat each slice completely dry. This is essential for getting a good roast instead of steaming the eggplant.

Part 2: Crafting the Rich Tomato Balsamic Sauce

While the eggplant is sweating, you can prepare your simple yet deeply flavorful tomato sauce.

1. Sauté the Aromatics: In a medium saucepan or skillet, heat 2 tablespoons of olive oil over medium heat. Add the minced garlic and red pepper flakes (if using) and cook for about 60 seconds until fragrant. Be careful not to burn the garlic.
2. Add Tomatoes: Open the can of whole tomatoes and pour the contents into the saucepan. Using the back of a wooden spoon or a potato masher, gently crush the tomatoes to your desired consistency.
3. Simmer and Season: Stir in the dried oregano. Bring the sauce to a gentle simmer, then reduce the heat to low. Let it cook, uncovered, for about 15-20 minutes, allowing the flavors to meld and the sauce to thicken slightly.
4. Finish the Sauce: Remove the sauce from the heat. Stir in the balsamic glaze and about half of your fresh basil leaves (you can tear them by hand). Season with salt and black pepper to taste. Set aside.

Part 3: Roasting the Eggplant Slices

Roasting the eggplant before assembling gives it a wonderful, slightly caramelized flavor and a creamy texture.

1. Preheat Oven: Preheat your oven to 400°F (200°C).
2. Oil the Eggplant: Arrange the rinsed and dried eggplant slices in a single layer on two large baking sheets. Drizzle or brush the remaining ¼ cup of olive oil evenly over both sides of the slices.
3. Roast to Perfection: Place the baking sheets in the preheated oven and roast for 20-25 minutes, flipping the slices halfway through. The eggplant should be tender, lightly browned, and slightly shrunken. It’s okay if it’s not fully cooked through, as it will continue to bake after assembly.

Part 4: Assembling and Baking Your Eggplant Towers

This is the fun part where your beautiful Napoleons come to life.

1. Lower Oven Temperature: Reduce the oven temperature to 375°F (190°C).
2. Prepare Your Pan: Take the same baking sheet you used for roasting (or a new one lined with parchment paper for easy cleanup).
3. Build the Stacks: Create your stacks directly on the baking sheet. For each Napoleon, follow this layering pattern:

   • Base: Start with one of the larger roasted eggplant slices.
   • Sauce: Spoon about a tablespoon of tomato sauce onto the eggplant.
   • Cheese: Place a slice of the patted-dry mozzarella on top.
   • Parmesan & Basil: Sprinkle with a little Parmigiano-Reggiano cheese and add one fresh basil leaf.

4. Repeat: Place a second eggplant slice on top and repeat the layering process: sauce, mozzarella, Parmesan, basil.
5. The Top Layer: Add a third and final eggplant slice. Top this slice with a generous spoonful of sauce, a final slice of mozzarella, and a heavy sprinkle of Parmigiano-Reggiano cheese. This top layer of cheese will get beautifully golden and bubbly.
6. Create All Stacks: Continue this process until you have used all your eggplant, creating 4 to 6 stacks depending on their size.
7. Bake to Golden, Bubbly Perfection: Place the baking sheet in the 375°F oven and bake for 15-20 minutes. The Napoleons are ready when the mozzarella is fully melted and bubbly, and the cheese on top is beginning to turn golden brown.
8. Rest and Garnish: Let the Napoleons rest on the baking sheet for 5-10 minutes. This is crucial for them to set up and will prevent them from collapsing when you move them. Garnish with the remaining fresh basil leaves and an extra drizzle of balsamic glaze before serving.