Add some oil to a pan and let it heat. Add cumin seeds and chopped white onion to the oil and cook for a minute.
Now, add stock/broth, lentil of your choice, carrots, and half a cup of milk. Cook for 15 minutes on medium flame.
Let it cool down to room temperature. Either with a hand blender or food processor, turn the mix into a puree.
Now cook again for a minute after adding cream, butter and a little water to the puree.
Serve with garlic bread, fresh parsley, croutons and a pinch of black salt.