Steps
1. Cook rice. Soak tamarind in 1 cup hot water for 30 mn.
2. Extract pulp; add 1/2 cup more water. Mix very well and strain pulp. Soak gram dal in 1/2 cup water for 30 mn; drain and dry on paper towel. chops red chilies.
3. Heat oil, add mustard seeds. As soon as seeds start split, add dal and saute for a minute; add tamarind pulp, turmeric powder, and salt.
4. Boil until mixture is like tomato paste. Add all spices that have been ground into powder; mix well; stir in the rice.
5. Leave on low fire till rice is done. To serve, garnish with roasted nuts.

Source
International Rice Institute (IRRI) & International Women's Organization (SUHAY), VIRMANI, Inderjeet (ED)(1991), Home Chefs of the World - Rice and Rice-based Recipes, ISBN 971-22-0023-X, Manila, Philippines