In a large stockpot over medium heat, add the avocado oil. When hot, add the onions and garlic. Saute until fragrant and slightly translucent, about 2 minutes.
Add the sausage and cook until no pink remains. Add the oregano, basil, parsley, red pepper flakes, salt, and pepper. Stir to combine.
Add the chicken broth, potatoes, and bay leaf. Bring to a boil then reduce heat to medium-high heat and gently boil for 15 minutes or until the potatoes are fork-tender. Taste the soup base and add more salt and pepper, if needed.
While the soup is cooking, whisk the almond milk and cassava flour until smooth.
After the potatoes are cooked, add the spinach/kale to the soup. Stir to combine and cook until wilted/thawed. Add the milk mixture and stir to combine, and cook for 1 minute to thicken.
Serve hot. Store leftovers in the fridge for up to a week.