Preheat your oven to 350F and lightly grease a 6"x9" baking dish.
Combine crushed tomatoes, olive oil, apple cider vinegar, minced garlic, fresh basil, herbs de Provence, salt, black pepper, and chili powder in a mixing bowl.
Pour the tomato mixture into the prepared baking dish and smooth it into an even layer.
Slice the onion, zucchini, eggplant, and fresh tomatoes, and arrange them in alternating patterns in the pan.
Optionally spray or brush olive oil over the tops of the vegetables.
Bake in the preheated oven for about an hour until the sauce is bubbling and the veggies are tender.
Let the Ratatouille cool for a few minutes, then garnish with fresh basil before serving.