In a large wok or saucepan, add the olive oil and place over medium heat. Once hot, add the eggplant and fry for 3-4 minutes, until slightly tender. Remove the eggplant from the heat.
Add the garlic and cook for 1-2 minutes, before adding the zucchini, onion, bell peppers, and tomato paste. Stir fry for 3-4 minutes, until the vegetables begin to soften.
Add the eggplant back, along with the tomato paste and crushed tomatoes, salt, and pepper. Reduce the heat to low and simmer for 20-30 minutes, until thick.
TO STORE: Store ratatouille in the refrigerator, covered. It will keep well for up to 2 weeks. TO FREEZE: Place leftovers in a freezer friendly container and store it in the freezer for up to 6 months. Thaw it completely before reheating.TO REHEAT: Either microwave for 1-2 minutes or place into a small saucepan and place over medium heat until bubbling and hot.