In a pan add 2 cup of water. To this add chopped tomato, 4 crushed garlic, rasam powder, turmeric powder, salt. Now with hand crush them all well. Cook and bring this to boil.
In a separate pan heat oil. add mustard seeds, cumin seeds, dry chili, curry leaf, 2 crushed garlic and sautae until the mustard seeds stop splattering and garlic raw smell is gone. Now add this to the boiling rasam. Cook the rasam for 2 or 3 minutes more.
Now add the lemon juice, coriander leaves to the rasam and remove from heat. Now the Rasam is ready to be severed.
Cooking time: 10 to 15 minutes.
You can add little lemon rind that's a different level of taste.