Prepare and cook the vegetables. Cut the eggplant, zucchini, and bell peppers into pieces, mix them together, and spread them on a baking sheet lined with parchment paper. Roast in a preheated oven at 350°F (180°C) for about 30 minutes.

Meanwhile, chop the onion and crush the garlic cloves. Sauté them in a saucepan. Peel the tomatoes, cut them into pieces, and set aside.

Once the vegetables are roasted, add them to the saucepan with the onion and garlic. Gently mix and heat over low heat. Add the chopped tomatoes, oregano, herbes de Provence, and salt. Continue cooking over low heat for about 20 minutes. You can serve this ratatouille with plain white rice or on its own. Enjoy!