Step 1

Combine 4 cups water, beans, onion and 2 garlic cloves in heavy large pot. Bring to boil. Reduce heat. Cover; simmer until beans are just tender, stirring occasionally, about 55 minutes.

Step 2

Add 6 cups water, 4 garlic cloves, potatoes, leeks, carrots, tomatoes with juices, half of green beans, half of zucchini, thyme and bay leaf. Bring to boil. Cover; simmer until vegetables are tender, stirring occasionally, 30 minutes.

Step 3

Add pasta to soup. Simmer 12 minutes. Add remaining green beans and zucchini to soup. Simmer until pasta is just cooked through but still firm to bite, about 5 minutes longer. Season to taste with salt and pepper. Ladle soup into bowls. Spoon 1 tablespoon Pistou atop each. Pass remaining Pistou separately.