In a Dutch oven or large sauce pan over medium heat, heat 3/4 of a teaspoon of the oil. Slice the onion and add it to the pan with a pinch of salt. Sauté for 10 minutes, until tender.
Cut the bell peppers into bite-size chunks. Add another 3/4 teaspoon of the oil to the pan, then the bell pepper. Toss to coat and sauté for 10 minutes or until tender.
Leaving the skin on, cut the eggplant into 1/2 inch cubes. Add another 3/4 teaspoon of that oil to the pan, then the eggplant. Toss and sauté for 10 minutes, or until tender.
Slice the zucchini into 1/2 inch thick rings. Add the remaining 3/4 teaspoon oil, then the zucchini. Toss and sauté for 10 minutes or until tender.
Chop the tomatoes into 1/2 inch chunks and add them to the pan. Cook for five minutes, then add the basil and time. Cover and cook for 20 minutes, or until soft. Stir in the vinegar and pepper to taste and serve.
This dish can be made ahead and reheated in the oven at 350° for 30 min. ￼￼￼￼ ￼￼