Rinse the chana dal and soak in water for 1 hour, then drain.

Heat ghee in a heavy saucepan over high heat. Add green chillies and fry until blistering. Add onions and cook until softened.

Lower heat to medium and add garlic, ginger, and curry leaves. Cook 1 minute until golden. Add tomatoes and cumin, cooking 2 minutes until paste-like.

Add drained lentils, water, turmeric, and salt. Bring to a simmer, cover, and cook gently for 1 hour, stirring 2-3 times.

Remove lid and simmer 30 minutes uncovered until thickened to a porridge-like consistency. Stir in garam masala and adjust salt.

For the tadka, heat ghee until very hot. Add cumin and mustard seeds until golden, then add dried chillies for 20 seconds, followed by sliced eschalot until tinged gold.

Pour the sizzling tadka immediately over the dal and stir through. Serve over steamed basmati rice garnished with fresh coriander.