Wash rice and lentils separately and soak them in water separately for 30 minutes. After 30 minutes, drain the water and keep it ready to use.
Take all the ingredients for Spice paste in a mixer jar and grind it to make a smooth paste. Add this paste to the potato pieces and mix it well. Cover the potatoes and keep it for 30 minutes.
Take ghee in a pressure cooker and add all the whole spices and saute it for a minute. Now add sliced onions to it and saute it until light pink in colour. Add potatoes with spice paste to it and cook it for 5 minutes.
Now add curd to it and mix everything well. Cook it until the oil separates. Now add rice and lentils to it. Add salt and three cups of water and cook it on high heat until two whistles. Let the pressure come down itself.
Serve hot tudkiya bhath with raita and papad.
