olive oil • onions (about 9 ounces/250 grams total) • garlic • medium yellow or green zucchini, unpeeled (about 3 pounds/1,400 grams total) • red and green bell peppers (about 1 pound/500 grams total) • ripe tomatoes, peeled if the skin is tough (1 kilogram) • ripe eggplant, unpeeled (about 1 pound/500 grams) • lovage • thyme • fresh oregano (or 1 teaspoon dried oregano) • small sprig rosemary (about 3 inches/8 cm) • medium handful fresh basil leaves •