Add the oil, carrots, onion, garlic, tomato and scallions to the pot, season with salt and pepper. Cook stirring occasionally about 12 minutes. Stir in the cumin and cook 1 minute more.

Add the lentils and water, bring to a boil. Then reduce the heat to medium low, cover and cook until the lentils become tender about 30 minutes.

Add the potatoes and cilantro, cook for 15 minutes until the potatoes are fully cooked and fork tender.

Using a blender, puree the soup in batches until smooth. Return the soup to the pot. Add more broth if needed to reach the desired consistency.

Ladle into soup bowls and top with cream, if using, and serve immediately.