In a large pot, add avocado oil. Add in the garlic, diced onion, diced carrot, and diced celery. Cook for 2-3 minutes until carrots and celery are soft, stirring frequently.
Add tomato paste, tomato sauce, and lentils to the pot and combine with the carrot and celery mixture. Cook for 1 minute.
Add canned potatoes to the pot.
Pour in 2 cups water and 2 cups chicken broth.
Add in black pepper, oregano and cumin. Stir to combine, cover, and bring to a boil.
Reduce heat to medium low and simmer for 25 minutes until lentils are cooked.
With a handheld emulsion blender, briefly emulsify about ¼ of the soup in the pot while leaving the texture chunky. If using a regular blender, remove ¼ of the soup and add the blender. Blend until smooth and place back in the pot.
Stir in spinach leaves into the soup and let simmer for 5 more minutes or until spinach is wilted.