Italian Ribollita (Vegetable and Bread Soup)

Ingredients

• 1 tablespoon olive oil
• 1 red onion large, diced
• 2 carrots diced
• 1 stalk celery diced
• 4 potatoes diced
• 10 zucchini 5 inch, diced
• 1 leek sliced
• 1 quart hot water
• 1 bunch Swiss chard chopped
• 1 head savoy cabbage quartered, cored and shredded
• 1 bunch kale shredded
• 31 ounces cannellini beans drained and rinsed
• salt and ground black pepper to taste
• 3 tablespoons tomato puree
• 8 slices day old bread