Rinse the moong dal thoroughly under cold water until the water runs clear, then soak for at least 30 minutes to help it soften and cook evenly.
Heat the ghee in a heavy-bottomed pot over medium heat until shimmering and fragrant.
Add the chopped onions and cook, stirring occasionally, until golden and fragrant, about 8 minutes. You should see them turn a warm, caramel color.
Stir in the grated ginger, garlic, and green chili; cook for another 2 minutes until aromatic and the mixture begins to sizzle.
Add the toasted cumin seeds, coriander powder, and turmeric to the pot, stirring briefly to toast the spices and release their fragrant aroma.
Pour in the vegetable broth or water, stirring to loosen any bits stuck to the bottom. Bring to a gentle simmer.
Add the soaked and drained moong dal to the simmering liquid, stirring well to combine.
Cover the pot and reduce the heat to low. Let the dal cook gently for about 40 minutes, stirring occasionally, until the lentils are tender and have a soft, creamy consistency.
Check the dal for doneness; it should be tender, slightly oozy, and flavorful. If needed, cook a little longer to reach the desired consistency.
Stir in the lemon juice to brighten the flavors and sprinkle with chopped cilantro for a fresh, herbaceous finish.
Serve the moong dal makhani hot, garnished with extra cilantro if desired. Enjoy the comforting, smooth, and smoky flavors with rice or bread.