Heat oil (or water if oil-free) in a large stock pot or Dutch oven over medium-high heat. Add the onion, celery, carrots, potatoes, and sweet potatoes and cook for 5 to 8 minutes, stirring occasionally, until softened slightly.
Stir in the cumin, ginger, smoked paprika, turmeric, cinnamon, sea salt, and black pepper, and cook for 2 minutes to bloom them and toast them slightly.
Add the lentils and tomato paste, really mixing well, and sauté for for another couple minutes. This helps to brown the tomato paste a bit.
Pour in the veggie broth, stir, cover, and and bring the soup to a boil. Lower the heat to medium-low and simmer for 20 minutes, or until the green lentils are al dente.
Add in the coconut milk, lemon juice, minced garlic, nutritional yeast and spinach and continue stirring until the spinach has wilted, about 2 minutes or so.
Taste and adjust seasonings before serving, then top with your desired garnishes. Enjoy with toasted crusty bread!
