Bring the chicken stock and water to a boil in a small pot.
Meanwhile, to a dry, large soup pot over high heat, add the lentils and all of the spices.
Stir the lentils and spices briefly and continue toasting until the spices are fragrant.
Add the boiling chicken stock and boiling water and stir everything to combine.
Add the mushrooms and tomatoes, reduce the heat to simmer, cover the pot with a lid and simmer for 8 minutes, or until the lentils and mushrooms are just soft and the tomatoes have burst. The lentils will absord some of the liquid, but not all of it. The consistency will be somewhere between a soup and a stew, but nowhere near a risotto. There will be a good amount of broth.
Add the chicken and simmer briefly, about 2 minutes.
Add the cream, stir to incorporate it completely, and simmer another 2 minutes, until everything is heated through completely.
Taste, and add salt and/or pepper, if desired.
Top with toasted cumin seeds, sour cream, fresh chopped cilantro and lime juice, if desired. Enjoy hot.