Soak dal overnight or for a few hours. Add the 3 cups of water with the turmeric and boil on the stovetop or in a pressure cooker until it's soft and smooth.
Heat butter ghee or oil and add mustard seeds, cumin seeds and fenugreek seeds. Once it starts bursting add spring onion (optional) curry leaf, chilli and onion and sauté until onion is translucent.
Add garlic and fry for a minute.
Add the tomato and cook on a low heat until the tomato is cooked.
Add the cooked da and season with salt, Add more water and bring to a boil, allow it to simmer on the stove for about 20 minutes. Water can be added according to your preference, if you prefer a thick dal add less water, if you prefer it more liquid then add more water. Once cooked you can add 2 teaspoons of butter to make it even more delicious if you wish.
Garnish with coriander