Put whole tomatoes in boiling water, simmer for 3 minutes, keep aside for 5 minutes.
Heat ¼ teaspoon clarified butter or cooking oil in a small pan, add peppercorns and 1 teaspoon of cumin seeds. Roast 'till aromatic, grind in a mortar or under a stone 'till powdered. Set aside.
Remove tomatoes from water, peel away the broken skin. Grate or mash 'till fine. To the thick pulp, add roasted whole chillies, all leaves, all masalas, salt, tamarind, jaggery and mash well either with hand or with a hand blender. The ingredients should have blended well into the pulp. Take in a deep pan, add stock or water. Heat clarified butter or oil in a small pan, add mustard and remaining cumin seeds, asafoetida and allow to splutter. Add garlic and stir, add carefully to the rasam. Bring to a boil, check spices and salt and adjust. Simmer for 2-3 minutes.
Set aside covered for 10 minutes before serving. Serve hot as a soup or with steaming hot plain rice and papads.
Note: Yield: 5 Servings, Ready In: 30 Minutes, Degree of Difficulty: Easy