Acquacotta - 'cooked water' - Tuscan Tomato and Pepper Soup

From my friend Lena Romano. Acquacotta - "cooked water" - Tuscan Tomato and Pepper Soup

In a large heavy pot, heat 1/2 cup of olive oil. Sauté 3 sliced onions until soft and transparent. Add 3 cloves of garlic and 3 stalks of celery, both thinly sliced. Remove the stems and seeds and cut into strips a large red pepper and a yellow one. Add to the pot along with 6 tomatoes, peeled, seeded and diced. Cook gently for about 1/2 hour. Season to taste with salt and pepper and pour in 3 cups of boiling water. Cook another 5 minutes and correct seasoning. Turn off heat.

Beat 4 large eggs with 1/4 cup grated parmesan, whisk quickly into the pot and serve immediately with buttered garlic toast.