While a lot of pre-mixed dosa batters are available in the market, I would suggest making the batter from scratch at home. It’s tastier, healthier, and more hygienic.
For dosa, cast iron tawas are the best as they add more crispiness. However, you can also use a non-stick pan.
Before pouring the batter, follow a few steps. First, let the pan heat and then add a few drops of oil. Later, sprinkle a few drops of water on it and let it sizzle. Wipe the pan with a cloth and then pour the batter on it.
Don’t flip the dosa too early. If you want a soft dosa, flip it after it’s cooked. However, if you want a crispy one, cover the dosa with a lid and let it cook without flipping.
For more crispiness, add a few tablespoons of suji (semolina) to the batter. Another thing to note is that your batter should be well-fermented and thin.