Rinse the red lentils under cold running water.

In a large pot, combine the rinsed lentils and water. Bring it to a boil, then reduce the heat to low and let it simmer for about 20 minutes.

While the lentils are cooking, heat oil or ghee in a separate pan. Sauté the diced onions until they are soft and translucent.

Stir in the minced garlic and grated ginger, cooking for about a minute.

Add the chopped tomatoes, turmeric powder, and cumin seeds to the onion mixture. Cook until the tomatoes break down, about 5 minutes.

Once the lentils are tender, add the onion-tomato mixture to the pot. Stir well to combine, adding salt to taste.

Let everything simmer together for another 5-10 minutes.

Blend the dal using an immersion blender if you prefer a smoother texture.