Heat the avocado oil in a large thick-bottomed pot such as a Dutch oven over medium-high heat. Sauté the onion, stirring occasionally, until it has softened and is starting to turn slightly golden brown, about 8 minutes. Stir in the garlic and cook for another 1-2 minutes, until fragrant.

Transfer the chicken thighs, chicken broth, and brown rice to the soup pot. Cover and bring it to a full boil. Add in the chopped cabbage and lemon zest and replace the cover. Cook at a gentle boil over medium-low heat for 1 hour.

Use tongs to remove the chicken thighs from the soup and transfer them to a cutting board. Use two forks to shred the chicken. Place the chicken back into the pot with the rest of the soup. Add in the white beans and chopped baby spinach and cover. Return the soup to a gentle boil if it isn’t there already and cook for 5 minutes to allow the spinach to wilt and the beans to heat up.

Taste the soup for flavor and add sea salt, black pepper, and/or fresh lemon juice to your personal taste. If you do dairy, feel free to grate some fresh parmesan cheese over your soup for serving.