Wash ginger well, peel off the skin and cut it into small pieces.
Heat 2 tsp of oil and fry the ginger pieces for 5-6 minutes on medium flame. Remove from pan.
Heat another teaspoon of oil, add mustard seeds and when it splutters, add urad dal, red chilies and curry leaves. Sauté until dal turns golden brown. Keep aside and let it cool.
Grind the sautéed dal along with ginger, salt and tamarind to a coarse paste. Do not add too much water.