Heat a large pot with oil, preferably olive oil, over medium heat.
When the oil is hot, add the onion and bell pepper. Mix well.
When the onion starts to become translucent, add the garlic pieces. Mix well so everything can brown.
When the onions and peppers are browned, add the eggplant, zucchini, and sprinkle with a pinch of salt. Mix well and let cook until the vegetables release some of their water.
When the vegetables are softened, add the remaining ingredients: tomato, water, bouillon, herbs, pepper, and olives if desired.
Reduce the heat, cover, and let simmer for about 30 minutes, mixing occasionally. Add water if it becomes too dry.
When cooked, the vegetables should look well-confited. Remove from heat and serve as a side with pasta, rice, a protein, or on its own for a light meal.