Microwave lemon for 15 seconds. Juice the lemon in a bowl and keep it aside.

Add chopped tomatoes with 2 cups of water in a sauce pan. Add ginger, rasam powder, a pinch of asafoetida, turmeric powder and let it cook for few minutes on low flame. Keep stirring in between.

Pressure cook lentil with 1/4 cup and mash it nicely.

Now add cooked dal into it and add some salt and mix it well. Let it simmer for few minutes. Remove from the flame, add squeezed lemon juice and mix it well.

Take a small frying pan and add ghee and mustard seeds to it. Once the seeds crackle, add curry leaves and asafoetida. Add this temperingit in rasam.

Garnish it with some coriander leaves. Enjoy it with rice or you can also drink it as a soup.