First, preheat the oven to 375˚F.
Toss eggplant in 1/2 tablespoon of salt and set aside to sweat for at least 10 minutes.
To make the sauce, set your skillet to medium heat on the stovetop and add your onion, garlic, and bell pepper. Sauté until fragrant, about 5-7 minutes.
Add seasonings: salt, pepper, oregano and optional red pepper flakes and let cook for another 2-3 minutes.
Add the peeled tomatoes and optional red wine to your pan. Let simmer on medium-low heat for 10-15 minutes. Taste and adjust seasonings accordingly.
Once your sauce is done, spread it evenly with a spatula.
For the eggplant, drain, rinse, and pat dry with paper towels.
To assemble the ratatouille arrange your eggplant, zucchini, and tomato in alternating patterns on top of the sauce until it fully covers the sauce. Sprinkle with parmesan, salt, and pepper.
Bake for about 45 minutes, or until the squash and eggplant are tender. Serve with fresh basil.