The best vehicle for making dosas undoubtedly is a well-seasoned cast iron griddle. A non-stick pan works too, but we have mostly dispensed with non-stick pans at home so I use a heavy old cast iron griddle that I have owned for ages. To prepare the griddle correctly, you need to heat is gradually until it’s very hot, turn down the heat, and season with oil. Use the cut onion half to rub the oil into the surface of the griddle till it’s glistening. Then, sprinkle the surface generously with water. As soon as it stops sizzling your pan is ready for the first dosa. (See video).