Ingredients
Urad saboot (whole black beans) 1 cup
Rajmah (kidney beans)  2 tbsp, soaked for 5-6 hours
Ghee or oil 1 tbsp
Water 6-8 cups  
Salt to taste 
Ginger 1" piece 
Garlic (optional) 4 flakes
Tomatoes 3, pureed in a grinder 
Onion, 1 chopped
Green chillies, 2 chopped
Cream ½ cup
Ghee or oil 3 tbsp
Dhania (coriander) powder 2 tsp
Garam masala (mixed spices) ½ tsp
Grated jaiphal (nutmeg) ¼ tsp
Cumin seeds, 1/2 tsp
Butter 1 tbsp
Chopped coriander leaves, to garnish

Method
Grind ginger and garlic together to a paste.
Clean and wash dals. Pressure cook dal and the soaked rajmah with 1 tbsp ghee, water, salt and half of the ginger-garlic paste. Keep the left over paste aside.
After the first whistle, keep on low flame for 40 minutes. Remove from fire. Keep aside.
In a pan, heat ghee.
Add cumin seeds and let it splutter. Add onion, cook till golder brown. Add tomato puree and green chillies. Cook until ghee separates and it turns thick. 
Add the left over ginger paste, garam masala & coriander powder. Cook for a few seconds. Add this tomato mixture to the boiled dal. Add butter.
Simmer slow fire for 8-10 minutes or till you get the required consistency, stirring occasionally. When done, remove from fire.
Garnish with cream and coriander leaves and serve hot.