Dal
Place lentils in a small-medium bowl and fill with water. Use your hand to swirl the dal around until the water becomes murky. Tip the bowl to take out the excess water and repeat until the water runs clear. Remove any debris and strain the excess water.
In a large pot, add dal and 9.75 cups of water. Bring this to a boil over medium-high/high heat. Once it comes to a boil, reduce the heat to low-medium to simmer. Use a slotted spoon to remove any white scum that rises to the top of the pot. Cover with the lid ajar. Cook, stirring occasionally, for 30 minutes or until the dal has no bite to it and can easily be mashed. Add water if needed to achieve desired consistency. Turn off the heat.
Tarka
In a separate large pan, heat oil over medium-high heat. Once hot, add the onions and sauté until slightly golden, about 7 minutes. Add the garlic and ginger and continue to sauté for about a minute. Add the tomatoes, tomato paste, spices, and salt. Cook until soft and you see the oil leaving the sides, about 3 minutes.
Bringing it all together
Stir the tarka into the cooked dal. Mix to combine.
Bring the dal to a simmer. Allow the dal to reduce for about 5 minutes, or until you achieve the desired consistency. Taste and adjust salt, if needed.
Serve dal hot with rice and/or plain yogurt.
