Wash the lentils in a colander until the water runs clear. Drain. Place the lentils in a large pot with the onion, garlic, squash, chickpeas, turmeric, and water. Bring to a boil and skim off any foam, then reduce heat to a low simmer and cook for about 40 minutes, stirring occasionally, until very soft with a puree-like texture.
Heat the ghee in a small skillet over medium heat. Add the onion and cook, stirring occasionally, until beginning to brown, 3 to 4 minutes. Add the cumin and mustard seeds, chili powder, and garam masala and immediately cover partially with a lid to keep the mustard seeds from popping out of the skillet. When the mustard seeds start to pop, remove from the heat.
Pour all the spice-infused oil into the prepared lentil soup and mix well to combine the flavors. Add salt to taste, and cook the soup, stirring, for several minutes. Ladle into bowls and serve garnished with fresh cilantro.
Adapted from “The Malaysian Kitchen” by Christina Arokiasamy.
