Soak tamarind in water and squeeze the juice. (You can also use tamarind paste mixed with water). The tamarind water should be one cup. Add sambar powder and turmeric powder to the tamarind water and stir well. Keep it aside.
Take out garlic flakes and peel the skin. Garlic flakes should be 10 to 15 Nos of medium size.
Chop onion finely.
In a kadai put a teaspoon of oil and fry the pepper first. When it starts pops up, remove. Add jeera in the same kadai and fry till it is hot to touch. Remove and keep it along with fried pepper. Same kadai add one more teaspoon of oil and add garlic flakes. Fry the garlic till it turns light brown. Remove and cool it. Grind fried pepper, jeera and garlic together to a fine paste. Wash the mixie with little water and add to the paste.
In a thick bottomed vessel, pour the remaining oil. When it is hot, add mustard. When it pops up, add chopped onion, curry leaves and fry just for second. Then Add tamarind water and stir well. Add salt and bring to boil. When it starts boiling, add the pepper paste and mix well. Allow to boil just for a second. No need to boil for longer time.
The kuzhambu is ready now. It tends to increase the body heat. So this kuzhambu is an ideal dish in cold weather.