In a mixture jar grind together black peppercorns, cumin, red chillies and garlic. Grind and make a coarse powder out of it.
Heat oil in a pot and add mustard seeds. When it crackles, add curry leaves and the spice powder to it and saute it for 2 minutes. Add turmeric, hing and coriander leaves to it and mix everything well. Now add finely chopped tomatoes or tomato puree and mix it. Add tamarind pulp, water and salt. Mix everything and let it come to a boil.
Simmer it for 15 minutes. Add water according to your requirement. Less water will give spicy and sour rasam. Adjust water according to your taste preference.
SServe hot rasam as a soup or along with a meal.
