Excellent. I did this with 600gm of tomatoes which makes enough for 4 bigish servings. Double all ingredients except for tamarind paste, be super careful with this, start with 1/2 teaspoon. 2 x teaspoons of salt, 3 x teaspoons of rasam powder and 2 x teaspoons of ground black pepper at the end.
This is great. I started with 2 x medium onions and added 1 x medium tomato along with the spice mix. I used roasted dessicated coconut that was run through a spice grinder.
Followed this to the letter and found the it quite bland and slightly bitter, the chilli overwhelmed the other flavours. This would probably be better with vegetable stock and 600ml instead of a litre.