Step 1Heat a heavy-bottomed pot over medium-high heat until hot. Add 1 1/2 tablespoons olive oil, then the onions and saute until lightly browned, 6 to 8 minutes, stirring frequently. Stir in the fennel and saute for 1 minute. Stir in the 5 cloves of garlic and continue to cook just until the garlic is aromatic, about 1 minute. Season with one-half teaspoon salt and one-half teaspoon of pepper.
Step 2Stir in the potatoes and carrots. Add 2 sprigs savory and the bay leaf, then pour in the water. Stir in another half-teaspoon salt.
Step 3Bring the water to a simmer, then reduce the heat so the water just "shivers"; it will steam with maybe one or two bubbles every once in a while. Add the rutabaga and cook, uncovered, for 20 to 30 minutes, until the vegetables are just tender.
Step 4Meanwhile, make the pistou. Place the parsley (reserving several leaves for garnish), the leaves of 3 sprigs of savory (reserving several leaves for garnish), 1 clove of garlic, the lemon zest, mustard and one-fourth teaspoon salt in a food processor and pulse to combine. With the food processor on, pour in one-half cup olive oil. Set aside.
Step 5Make the croutons. Heat the oven to 375 degrees. Heat 1 1/2 tablespoons olive oil with 1 clove garlic in a pan over medium heat. Add the bread cubes and 1 sprig savory. Saute, tossing frequently, until the bread is well-browned on the edges, about 3 minutes. Place the bread on a baking sheet and toast until the bread is dried through, about 5 minutes.
Step 6When the soup is ready, taste and adjust the seasoning if needed. This makes about 2 quarts soup. Ladle the soup into bowls. Top each with a few croutons and a dollop of pistou. Garnish with parsley and savory and a grind of pepper. Serve immediately.