Grind the sabudana and samak rice separately, then sift them.

Mix in the yogurt, rock salt, and water to make a thick batter. Set aside for 20 minutes.

Boil and peel the potatoes. Finely chop the ginger and green chilies.

Heat ghee in a pan. Add cumin seeds and cashews, and roast on low heat. Add green chilies, ginger, and curry leaves.

Mash the boiled potatoes and add them to the pan. Mix in rock salt and black pepper powder. Stir in the chopped cilantro to finish the potato filling.

Lightly grease a nonstick skillet with ghee. Sprinkle some water and wipe with a tissue. Pour the dosa batter onto the skillet and spread it in a circle.

Cook on low heat until lightly golden. If needed, add ghee around the edges. When the edges start to lift, place the potato filling in the center and fold the dosa.

Serve the crispy sabudana dosa hot with a mild cilantro chutney.