Heat oil in a Dutch oven or large saucepan over medium heat.
Add the finely minced garlic and chopped onion and cook until tender and fragrant.
Cut the eggplant, zucchini, and green peppers into uniform 1-inch pieces.
Add the chopped vegetables to the pot along with the oregano, basil, and parsley, stirring to combine.
Sauté the vegetables for about 5 minutes until they begin to soften.
Stir in the crushed canned tomatoes and season with fresh ground pepper to taste.
Cover the pot, reduce the heat to low, and simmer for about 45 minutes.
Cook until all the vegetables are tender and the flavors are well blended.
Serve hot or allow to cool and refrigerate to enjoy chilled later.