To a Dutch oven or large soup pot heat the ghee and saute onions and chiles for 2 minutes and add remaining Soup ingredients along with drained lentils.
Bring to a boil, lower heat and simmer, covered, for 30 minutes.
In a large skillet over medium heat add the ghee and cumin seeds. When they begin to sputter and crackle, add remaining tadka ingredients, stirring and saute on low for 2 minutes.
Using a potato masher or immersion blender (stick blender) mash to desired consistency. I like to leave it slightly chunky and loose. Season to taste.
Serve with cilantro and tadka spooned over each bowl of lentils.
Notes
1. Substitute with combination of 1/2 split pigeon pea lentils (arhar dal) and 1/2 cup red lentils (masoor dal).