Add the olive oil, onion, celery, and garlic to a large stockpot or dutch oven. Turn the heat on medium-low and sauté for 5 minutes, or until the veggies are soft and translucent, stirring occasionally.
Add the vegetable broth, and stir to combine.
Increase heat to medium high and bring to a boil. Then, reduce the heat to low, cover, and simmer, for 15 minutes.
Meanwhile, add the chives, parsley, basil, tarragon, nutritional yeast, apple cider vinegar, sea salt, and cayenne pepper to a high-speed blender. Set aside (do not blend yet).
Place a sieve or fine mesh colander over another large pot. Carefully pour the hot broth over the sieve to separate the vegetable solids from the broth. Reserve the veggies for another use or discard.
Carefully pour the broth into the blender with the herbs.
Blend on high until smooth. The broth should take on a vibrant spring green hue.
You can enjoy the broth as is or, to soften the bite of the herbs, return it to the stockpot and simmer over low heat for just 1 to 2 minutes, or until warmed through and the flavors meld.
Taste and add more sea salt if desired (I usually add another ⅛ to ¼ teaspoon).
Serve the broth warm in mugs or bowls.
Leftovers can be refrigerated for up to 3 days or frozen for up to 1 month.