Wash and peel the potatoes. Grind them to a fine paste.
Transfer this paste to a mixing bowl.
Add salt, semolina, chickpea flour and Rice Flour. Add water. With the help of a whisker, mix it well till there are no lumps in the batter.
Add onion, coriander, curry leaves, green chillies, and cumin seeds.
Mix well. Rest this mixture for about 15 minutes.
After 15 minutes, mix the batter well. The batter should be thin ( Like Rava Dosa Batter).
Heat a pan. When it is medium hot, drop portions of the batter on the pan to form a netted structure.
Drizzle oil on the sides as well as the surface of the dosa. On low to medium heat, let it cook, till you see it browning on the lower surface.
Remove from heat and serve hot with any chutney of your choice. Hot crispy dosas are ready.