Pressure cook both the dals along with some salt and turmeric till done. A lot of people complain that dal leaves a lot of water while boiling in a cooker. For me what works to solve this is - pre soaking the dal and adding 1/4 tsp of oil at the time of boiling. Once the dal is boiled, set aside for cooling.
In a kadhai, heat ghee and add heeng to it. Once it is fragrant and slightly browned, add jeera seeds and fry till golden brown.
Add the onions and saute till the onions are golden brown. Add the tomatoes and saute till they are soft and well roasted.
Add the Tata Sampann Dal Tadka masala, boiled dal and if required some hot water. Bring to boil together and simmer for 2-3 minutes. Sprinkle coriander leaves and turn off the gas.
Serve hot with phulkas, steamed rice or pulao.