Heat a large skillet or pot over medium heat and add the olive oil.

Once hot, add the diced eggplant and cook for about 5 minutes, stirring occasionally. Season with salt and pepper and set aside.

Add the chopped zucchinis to the skillet and cook until lightly browned. Set aside.

Add diced red and green bell peppers to the skillet and sauté until tender and slightly golden. Set aside.

In the same skillet, add more olive oil if needed and sauté the sliced yellow onion until soft and translucent, about 2 minutes.

Add the minced garlic and cook for another minute until fragrant.

Add the roughly chopped tomatoes and let the mixture simmer for about 5 minutes.

Add all the reserved cooked vegetables back into the pot, sprinkle in the herbes de Provence, and adjust seasoning.

Cover and let it simmer over low heat for 15 to 20 minutes, avoiding stirring too much to keep the vegetables intact.

Taste and adjust seasoning if necessary before serving.