Make-Ahead Mushroom Tomato Bread Soup Recipe

Ingredients (10)

• 1 (6-inch) ciabatta loaf or any stale bread, torn into 1-inch chunks (about 2 cups torn bread)
• 1 tablespoon olive oil
• 1 medium yellow onion, diced (about 1 cup)
• Kosher salt
• 1 1/2 tablespoons apple cider vinegar
• 12 ounces cremini mushrooms, halved if small, quartered if very large
• 1 (14.5 ounce) can diced tomatoes
• 1/2 teaspoon ground cinnamon
• 3 cups low-sodium vegetable or chicken stock, plus 1 more cup as needed
• Freshly ground black pepper