Heat the olive oil in a large pot or Dutch oven. Add the onion, carrot, and celery. Cook for about 5 minutes until softened. Stir in the garlic and cook for another minute until fragrant.
Add the cumin, paprika, and salt and stir well to combine.
Stir in the tomato paste and cook for a minute more. Next, add the crushed tomatoes, green lentils, and vegetable stock. Bring to a boil, then reduce heat and simmer for about 30-35 minutes or until the lentils are tender.
Next, stir in the shredded Tuscan kale and continue to cook for a couple more minutes until the kale has wilted.
Stir in the flax seed, adjust the seasoning to taste and serve hot, sprinkled with some extra flax seed if you like.
