• Prep. Preheat oven to 450ºF. Line a baking sheet with aluminum foil and spray with cooking spray.
• Salt and pre-bake the eggplant. Arrange eggplant slices on the prepared baking sheet and sprinkle each slice with salt; let stand 20 minutes. Using paper towels, wipe off the moisture from each slice and bake for 10 to 12 minutes, or until browned on top.

To Make the Tomato Sauce

• Sauté. In a large skillet, heat olive oil over medium heat. Add onions and peppers; season with salt and pepper and cook until tender, about 4 minutes, stirring frequently. Stir in the garlic and continue to cook for 20 seconds.
• Mix the remaining ingredients. In a mixing bowl, combine the tomato sauce, light brown sugar, Worcestershire sauce, Italian seasoning, and parsley. Mix until thoroughly combined.
• Combine. Add tomato sauce mixture to the onion mixture and cook for 1 to 2 minutes or until heated through.

To Assemble

• Take out the eggplant. Remove eggplants from the oven. Lower the oven temperature to 350ºF.
• Prepare a baking dish. Lightly grease a baking pan or a casserole dish with cooking spray or you can use the same baking sheet that you used for roasting the eggplants.
• Assemble. Cover the bottom of the baking dish with about 1/4 to 1/2 cup tomato sauce. Place the 4 largest eggplant slices over the tomato sauce. Over each slice of eggplant, spread a couple of tablespoons of tomato sauce and sprinkle with mozzarella cheese. Repeat layers, ending with cheese. Each stack should consist of 3 slices of eggplant.
• Bake. Bake uncovered for 15 minutes, or until the cheese is melted and the tops turn light brown.
• Serve. Remove the eggplant stacks from the oven and serve.