The basic dosa recipe calls (or soaking urad dal/skinned black lentils and rice. The soaked lentils and rice are then finely ground and fermented overnight. Warm temperature is important for the dosa batter to ferment well. Methi seeds are added to aid the fermentation process. The masala in the Dosa is a potato sabzi. The easiest and simple version of it is where lot of onions are added to the potato filling. Once the dosa batter is ready take a spoonfull and pour it on the griddle. Spread the batter in a circular manner to get a thin and round dosa. Pour some oil on the top and edges. Flip and cook the other side. Flip again. Now add the potato masala on the dosa. Remove from the griddle and serve masala dosa hot with spicy sambhar and coconut chutney.