In a large saucepan, heat the ghee and add the dhal, mustard seeds, ground coriander, ground cumin, turmeric, cinnamon stick, garlic, minced ginger, curry leaves, onion, and green chilly pepper. Cook over low heat for 5 minutes until the spices are fragrant and deep brown in color and the onion has softened.
Add the vegetable broth and simmer until the dhal is spft, about 30-45 minutes.
Remove the cinnamon stick, green chilly pepper and curry leaves.Blend the dhal until smooth with a hand-held electric beater, then return to the saucepan.
Add the diced vegetables and simmer for a further 20 minutes or until the vegetables are soft.
Add the lemon juice, salt to taste, and chopped coriander. Stir well and serve with a dollop of yogurt, garnished with a few coriander leaves.