1. Soak 1.5 cups sabut urad dal / whole black gram in enough water overnight.
2. Add soaked whole black gram / sabut urad dal, 1/2 cup chana dal / split bengal gram, salt to taste, 1/2 tsp turmeric powder, 1/2 tsp red chilli powder, 1/2 inch chopped ginger, 3-4 chopped garlic and 1 bay leaf to a pressure cooker. cover and pressure cook for 4-5 whistles till lentils turn soft.
3. Meanwhile, heat 2 tbsp ghee and 1 tbsp oil in a pan, add 1 tsp cumin seeds and allow to splutter.
4. Add 1 inch ginger, 3-4 crushed garlic cloves and 2-3 coarsely ground green chillies, saute till fragrant.
5. Add 3 medium sized sliced onions and saute till they turn golden. add 1/4 tsp turmeric powder, 1 tsp coriander powder and 1 tsp red chilli powder, mix well and cook for 3-4 minutes.
6. Add 1 small finely chopped tomato and saute till the ghee begins to separate.
7. Open the pressure cooker, mash the lentils a little with the back of a spoon/spatula.
8. Transfer dal into prepared tadka along with chopped coriander leaves and mix well.
9. Garnish with coriander sprig and serve hot.