Wash the lentils (see the "washing lentils" section above for how to wash them properly).
Add the four cups of water into a pot and place on the stove over medium-high heat. Stir in the lentils, salt and turmeric.
Keep stirring until the lentil grains are cooked and soft, and the water is evaporating; the water and lentils are not seen separately but they are more mixed into a type of gravy. This will take 30 minutes.
In a separate pan, prepare the seasoning.
Add oil over medium heat. As the oil heats up, add the cumin seeds.
When you see the cumin seeds splattering/sizzling (after less than a minute), add the chopped onion and garlic. Saute this mixture for a few minutes (around 4 minutes).
Now add the ginger and garlic. Stir for 2 minutes.
Add tomato, red chili powder and coriander powder while continuing to stir.
After about 30-45 seconds of stirring the mixture, add half the cilantro and stir one last time.
Now pour this seasoning into the lentils in the other pot, which should be cooked after around 30 minutes. If it hasn't been that long, set aside the onion mixture until the lentils are ready. They should be tender and easily break when pinched with your fingers.
Once the lentils are ready, pour in the onion mixture.
Pour the soup into six serving bowls, and garnish with cilantro before serving.
Enjoy hot!