Step 1Prepare the garbanzo beans: Soak the beans in water overnight, then drain and rinse. Place in a saucepan with water to cover and simmer until tender, about 45 minutes. Drain and set aside.
Step 2Prepare the red pepper and tomatoes: Char the pepper under a broiler, then peel, seed and slice into strips. Repeat with the tomatoes, broiling until charred, then seed and chop.
Step 3Using a large sauté pan, brown the onions in a little of the olive oil, stirring frequently.
Step 4Add the garbanzo beans, red pepper, tomato and squash, along with enough water to surround the ingredients but not submerge them. Bring to a simmer and cook, loosely covered, until the squash is very tender, 40 to 50 minutes. Taste and season with salt, pepper and the remaining olive oil and a splash of good vinegar.