Heat first amount of oil in large heavy skillet. When quite hot, add eggplant; cook, stirring constantly, for about 3 minutes. With a wooden spoon, remove eggplant to colander. Next cook zucchini in skillet, stirring constantly, about 3 minutes. Remove to colander also. Add remaining oil to skillet; saute onion until clear. Add green pepper to skillet, and cook while stirring, for about 3 minutes. Stir in garlic, thyme and bay leaf. Add drained eggplant and zucchini. Cook while stirring, for about 5 minutes. Add tomatoes, cover tightly, and cook for 20 minutes. Uncover and cook for about 10 minutes to reduce liquid that will have accumulated. Serve hot or cold.