1. Prepare tomatoes. Heat oven to 225 degrees. Drop the tomatoes into a pot of boiling water, and, if necessary, weigh them down with a heavy slotted spoon, to keep them from floating. After 2–3 minutes, test by pulling off a bit of skin with a paring knife. If it comes off easily, pull tomatoes out, one by one, and drop them into the ice bath. After a minute or two, retrieve them and peel off the skin.
2. Place a sieve over an empty bowl. Cut the peeled tomatoes into quarters, then scoop out the seeds with a spoon and place them into the sieve. Set aside.
3. Line a sheet pan with parchment paper. Brush the paper with olive oil and season it lightly with salt and sugar. Place tomatoes on the paper cut-side down and brush them, too, with the oil. Cook for about 40 minutes, until they are cooked but still firm. Cool and set aside.
4. While tomatoes roast, stir the tomato pulp and seeds in the sieve vigorously with a spatula or wooden spoon, to extract the maximum possible liquid. You should have between ½ cup and 1 cup. Pour the liquid into a saucepan, place over low heat, and simmer, gently, until the volume is reduced by half. Set aside.
5. If you are using saffron, hydrate in water and set aside.
6. Prepare peppers. Raise the oven temperature to 425 and insert a medium-sized tray. When hot, remove the tray and splash with olive oil, then add peppers and, with a pair of tongs, roll them in the oil to cover. Return the tray to the oven. Check after ten minutes. If the peppers have begun to brown, flip them with the tongs. Check after another 10 minutes and repeat, until peppers are nearly black on all sides. Remove the tray from the oven and, if needed, wrap peppers in a piece of aluminum foil (the trapped steam helps loosen the skin). When peppers are cool enough to touch, peel off the skin with a paring knife. Remove the stems and seeds and cut peppers into quarters.
7. Prepare onion. Heat a sauté pan over a low flame. Season onion with salt and pepper. Increase the heat to medium-high and add 1-2 Tbsp. olive oil to the pan. Add onion and cook, tossing occasionally until soft but not browned. Drain in a colander to remove excess oil and set onion aside.
8. Prepare eggplant. Wipe out the sauté pan and place over a low flame. Season eggplant with salt and pepper. Increase the heat and add a little less than 1 Tbsp. of olive oil to the pan. Add eggplant—don’t move or shake until it begins to color slightly. Flip eggplant with a spatula and cook until tender. Drain in a colander and set aside.
9. Begin assembly. Place a medium pot on a low burner. Chop tomatoes into bite-size pieces and add to the pot, then add 2 Tbsp. of tomato water. Chop peppers into bite-size pieces, then add to pot and stir. Add onion, then eggplant. If the mixture seems dry, add more tomato water. Add garlic and bouquet garni. Add saffron, if using. Cover. Check after 5 minutes to insure that the mixture is not boiling. Stir gently. After another 5 minutes, remove lid, stir, and simmer.
10. Prepare zucchini. Cut zucchini into bite-size pieces and toss in a bowl with 1 Tbsp. olive oil, a few twists of black pepper, and reserved thyme leaves. (Do not salt: salt will liquify zucchini and prevent them from crisping up.) Heat a sauté pan over a high flame and add zucchini. Toss occasionally, until zucchini show color but are still crisp: that is, bright green with bite. Remove from the pan and drain in a colander, then salt to taste.
11. Finish assembly. Taste for seasoning and for moisture, and add more salt and pepper and tomato water as needed. Add vinegar, then mix in zucchini and let cook until heated through. Add olives if you’re using them . Remove bouquet garni and garlic. Dress with torn basil leaves. Serve with roasted chicken, French fries, toast, nothing at all, or just about anything.