Start by washing the herbs and tying them together in a little bundle using kitchen twine, or kitchen string. Set aside.
In a large pot, heat a bit of extra virgin olive oil over medium heat and sauté the carrot, onion, and garlic for a minute or two until the onion turns translucent.
Add the pre-soaked beans, water, bay leaves, the herb bundle, and the lemon peel. Cover with a lid and bring to a simmer. Once simmering adjust the lid to leave a small opening and leave the beans to simmer for one hour.
After one hour taste the beans to get a feel for how much longer they will need to cook. Most fresh beans are done in 45 minutes to 1 1/2 hour but the older the beans the longer they take to cook. Hence the need to check. Keep simmering until the beans are almost done. You will want them to still have a bit of bite.
Once your beans are almost done adjust the seasoning by adding salt and pepper, then add the potatoes. Don't go overboard on the salt. The liquid will be reduced some more which will concentrate the saltiness. You will be correction the seasoning at the very end.
Simmer until the potatoes are done, about 10 to 15 minutes more.
Drain the liquid into another pot and boil it at high heat until reduced to about 3 cups, then turn down to a simmer.
While the soup is being reduced, fish out the bay leaves and the herbs from the beans and discard.
Mix the cornstarch with a little cold water in a small bowl or cup and add it, a little at a time, to the hot soup. You just want to thicken it a little bit so you may not need all of it.
Pour the now slightly thicker soup back into the pot with the beans and potatoes and add the spinach. Stir for a minute until the spinach has wilted.
Add the nutritional yeast and correct the seasoning to taste.