Provencal Soup with Pistou

Fall and soup just go together, so when I saw Ina making this one for her French friends, I knew I had to give it a whirl.  So healthy and yummy looking!  And if you make it with veggie stock, it's totally vegan as well.

2 tablespoons good olive oil
2 cups chopped onions (2 onions)
2 cups chopped leeks, white and light green parts (2 to 4 leeks)
3 cups 1/2-inch-diced unpeeled boiling potatoes (1 pound)
3 cups 1/2-inch-diced carrots (1 pound)
1 1/2 tablespoons kosher salt
1 teaspoon freshly ground black pepper
3 quarts homemade chicken stock or canned broth
1 teaspoon saffron threads
1/2 pound haricots verts, ends removed and cut in 1/2
4 ounces spaghetti, broken in pieces
1 cup Pistou, recipe follows
Freshly grated Parmesan, for serving

Heat the olive oil in a large stockpot, add the onions, and saute over low heat for 10 minutes, or until the onions are translucent. Add the leeks, potatoes, carrots, salt, and pepper and saute over medium heat for another 5 minutes. Add the chicken stock and saffron, bring to a boil, then simmer uncovered for 30 minutes, or until all the vegetables are tender. Add the haricots verts and spaghetti, bring to a simmer, and cook for 15 more minutes.

To serve, whisk 1/4 cup of the pistou into the hot soup, then season to taste. Depending on the saltiness of your chicken stock, you may need to add up to another tablespoon of salt. Serve with grated Parmesan cheese and more pistou.

Pistou
4 large garlic cloves
1/4 cup tomato paste
24 large basil leaves
1/2 cup freshly grated Parmesan
1/2 cup good olive oil

Place the garlic, tomato paste, basil, and Parmesan in the bowl of a food processor and puree. With the motor running, slowly pour the olive oil down the feed tube to make a paste. Pack into a container, pour a film of olive oil on top, and close the lid.