Lentil Fennel Soup w Herbs

I remain mystified as to how a bag of red lentils resulted in a yellow soup...
Anyway, this was a delicious combination of fresh ingredients that resulted in a hearty, herbed lentil soup. I love fennel and used the entire head of it here. Usually just the bottom part is used, but I added the top fronds as well. This essentially acted as the dill element. One of my girls asked me to fully purée the soup, but feel free to play around with consistency with your immersion blender.

Ingredients:
A bag of lentils, I used red, rinsed
10 cups vegetable stock or broth
A Spanish onion, diced
A large head of fennel, chopped from top to bottom
A cup of packed, fresh basil
A bouquet garni of fresh rosemary and thyme, I used 2 sprigs rosemary and half a bunch of thyme
One large dried bay leaf
One tsp each dried Italian seasoning and cumin
Two tbsp red wine vinegar

In a large soup pot sauté the onions in several tbsp olive oil, until fragrant and translucent. Add the vinegar as the onion starts to brown. Add the cumin and Italian seasoning, cover pot and let all combine. After a couple minutes add the chopped fennel bulb and fronds with a cup of the stock. Stir, cover, and sweat the onions and fennel. This gives the soup a terrifically flavorful base. Let sweat for several minutes. Uncover pot, add the rest of the stock, the lentils, the basil, and all the dried herbs. Add 1 1/2 tsp salt and 1 tsp fresh ground pepper. Mix well, cover, and bring to a boil on medium high heat. Lower heat and simmer for an hour. Remove from heat, remove the bay leaf and bouquet garni. Let cool for ten minutes then taste to adjust seasonings. Blend to desired consistency. Garnish with a sprig of fresh thyme.