- In large pot over medium heat, heat the olive oil. Add the garlic and onions. Cook, stirring, until the onions are transparent, 4 to 5 minutes.
- Add the eggplant and cook, stirring, for 2-3 minutes. Stir in the zucchini, bell pepper, and tomatoes and cook, stirring, for 5 minutes more.
- Crumble up the chicken cubes and add to the mixture, as well as the balsamic vinegar, olives, Italian seasoning, and the salt and black pepper to taste.
- Reduce the heat to medium-low and stir well. Cover and cook until the vegetables are softened, about 5 minutes more.
- Top the hot servings of ratatouille with Parmesan cheese, and optional red pepper flakes.